Given that:
Cost of the washer/dryer = $900
Number of payments made = 24
Amount paid in each payment = $46.23
Total amount she paid
[tex]\begin{gathered} =\text{Amount paid in each payment}\cdot Number\text{ of payments} \\ =46.23\cdot24 \\ =1109.52 \end{gathered}[/tex]Interest paid = Total amount paid - Cost of the washer/dryer
[tex]\begin{gathered} =1109.52-900 \\ =209.52 \end{gathered}[/tex]Option d is correct.
Find the domain of the rational function.f(x)=x−1/x+4
Given:
[tex]f(x)=\frac{x-1}{x+4}[/tex][tex]\begin{gathered} \text{Let, x+4=0} \\ x=-4 \end{gathered}[/tex]Domain:
[tex]-\infty<-4<\infty[/tex][tex](-\infty,-4)\cup(-4,\infty)[/tex]Where can I find L1 and L4 for a missing vertical angles?
The vertical angle theorem states that the opposite angles formed by two lines that intersect each other are always equal to each other.
Then, if we apply this to the figure shown we can say that by the vertical angle theorem
[tex]\begin{gathered} L1=L3 \\ L2=L4 \\ Meaning\colon \\ L1=45.5 \\ L4=134.5 \end{gathered}[/tex]Zales sells diamonds for $1,100 that cost $800. What is Zales’s percent markup on selling price? Check the selling price.
Zales's percent markup on the selling price as required in the task content is; 37.5%.
Percentages and markup priceIt follows from the task content that the percent markup on the selling price be determined according to the given data.
Since the cost of diamonds is; $800 while the diamonds sell for $1,100. It follows that the markup on the selling price of the diamonds is;
Markup = Selling price - Cost price.
Hence, we have;
Markup = 1,100 - 800.
Therefore, the markup is; $300.
On this note, the percent markup can be determined as follows;
= (300/800) × 100%.
= 37.5%.
Ultimately, the percent markup on the diamonds is: 37.5%.
Read more on percentages;
https://brainly.com/question/19247356
#SPJ1
LE Answer two questions about Systems A and B: System A System B 3.7 +12y = 15 x+4y=5 10y = -2 73 - 10y = -2 1) How can we get System B from System A? Choose 1 answer: A Replace one equation with the sum/difference of both equations B Replace only the left-hand side of one equation with the sum/difference of the left-hand sides of both equations C Replace one equation with a multiple of itself D Replace one equation with a multiple of the other equation 2) Based on the previous answer, are the systems equivalent? In other words, do they have the same solution? Choose 1 answer: А Yes B No
The first equation from System A is what is called a linear combination of the first equation of System B: the equation are equivalent.
System A equation is equal to the System B equation multiplied by a factor of 3 on both sides, so they contain the same information.
Answer: Yes. The systems are equivalent as their equations are equivalent.
Charlie buys a new car with a sticker price of $9,684. For the down payment,he trades in his old car for $1,400. He finances the balance and makes36 monthly car payments of $253. What is the total amount paid for thecar, including interest?
The total amount = 36 x 253 + 1400 = 9108 + 1400 = $10508
Therefore,
the total amount paid with interest $10508
Function g is a transformation of the parent function exponential function. Which statements are true about function g?
For the given function, The following are true statements:
Four units separate function g from function f.There is a y-intercept for function g. (0,4)Function g has a range of (3,∞ ).Over the range (-, ∞), function g is positive.It may be seen from the graph below that
The g function's graph is 4 units higher than the parent exponential function's graph.
All of the input values for which the function is defined are referred to as the function's domain. The domain of the function is (-, ∞ ) according to the graph of function g.
The location where a function's graph crosses the y-axis is known as the y-intercept. G's graph crosses the y-axis at (0, 4). As a result, the Function g's y-intercept is (0,4).
growing function g across the range (- ∞, 0).
Function output values are referred to as the function's range. It can be seen from the graph that the range of function g is (3, ∞ ).
To learn more about functions, https://brainly.com/question/21145944
#SPJ9
You start driving north for 5 miles, turn right, and drive east for another 12 miles. At the end of driving, what is your straight line dissonance from you r starting point?
You start driving north for 5 miles, turn right, and drive east for another 12 miles
The angle between north and east = 90
So, x is the hypotenuse of the triangle
[tex]x=\sqrt[]{5^2+12^2}=\sqrt[]{25+144}=\sqrt[]{169}=13[/tex]so, the length = 13 miles
The sum of two numbers is 40. If 2 is added to the larger number, theresult is equal to twice the smaller number. What are the two numbers?
We have 2 numbers. We can call them x and y, being x the smaller one.
The sum of this two numbers is 40, so we can write:
[tex]x+y=40[/tex]We know that if 2 is added to the larger number (that we name as y), the result is twice the smaller number, that would be 2x. Then, we can express this as:
[tex]y+2=2x[/tex]We can express y in function of x from the second equation and then replace it in the first equation to solve for x:
[tex]y+2=2x\Rightarrow y=2x-2[/tex][tex]\begin{gathered} x+y=40 \\ x+(2x-2)=40 \\ 3x-2=40 \\ 3x=40+2 \\ 3x=42 \\ x=\frac{42}{3} \\ x=14 \end{gathered}[/tex]Now, we can calculate y as:
[tex]\begin{gathered} y=2x-2 \\ y=2(14)-2 \\ y=28-2 \\ y=26 \end{gathered}[/tex]Answer: the two numbers are 14 and 26.
Greg is ordering tile for a floor he is installing. The owner picks out tile that is 16in by 16in including the grout . The floor is 350 sq ft . (part 1) How many tile must Greg order for the floor ( assume no waste)(part 2) Each tile cost $ 1.75 plus 8% sales tax . How will the tile cost ?
ANSWER
(part 1) 196 tiles
(part 2) $ 1.89
EXPLANATION
(part 1)
First we have to find the area of each tile, that is the product of the dimensions because it is a rectangle,
[tex]A_{\text{tile}}=16in\cdot16in=256in^2[/tex]To compare it to the floor's area, we have to transform it into square feet. Knowing that 1 ft² = 144 in²,
[tex]256in^2\cdot\frac{1ft^2}{144in^2}=\frac{16}{9}ft^2[/tex]This is a partial result, so it is best if we leave it as a fraction so we don't miss any decimals.
Now, the area of the floor is 350 ft². To find how many tiles Greg has to order, we have to divide the area of the floor by the area of each tile,
[tex]\#tiles=\frac{A_{\text{floor}}}{A_{\text{tile}}}=\frac{350ft^2}{\frac{16}{9}ft^2}=196.875[/tex]But the number of tiles has to be an integer. If Greg buys 197 tiles they will have to cut some (waste). If he buys 196 there will be some of the floor not covered. However we were asked to assume no waste, so Greg will have to order 196 tiles.
(part 2)
To answer this question we have to add 8% to the cost of the tile. The 8% of 1.75 is,
[tex]1.75\cdot\frac{8}{100}=0.14[/tex]So the cost of each tile is,
[tex]1.75+0.14=1.89[/tex]Given the conversion factor which cube has the larger surface area?
Given the surface area of a cube as
[tex]\begin{gathered} SA=6l^2 \\ \text{where l is the length} \end{gathered}[/tex]Given Cubes A and B
[tex]\begin{gathered} \text{Cube A} \\ l=19.5ft \end{gathered}[/tex][tex]\begin{gathered} \text{Cube B } \\ l=6m\text{ } \\ \text{ in ft}\Rightarrow\text{ 1m =3.28ft} \\ l=6\times3.28ft=19.68ft \end{gathered}[/tex]Find the surface area of the cubes and compare them to know which one is larger
[tex]\begin{gathered} \text{Cube A} \\ SA=6\times19.5^2=6\times380.25=2281.5ft^2 \end{gathered}[/tex][tex]\begin{gathered} \text{Cube B} \\ SA=6\times19.68^2=6\times387.3024=2323.8144ft^2 \end{gathered}[/tex]Hence, from the surface area gotten above, Cube B has a larger surface area than Cube A
Suppose the purr of a cat has a sound intensity that is 320 times greater than the threshold level. Find the decibel value for this cats purr. Round to the nearest decibel.
The decibel value for this cats purr round to the nearest decibel is; 25
How to calculate the decibel level?Decibel (dB) is a unit for expressing the ratio between two physical quantities, such as measuring the relative loudness of sounds. One decibel (0.1 bel) is equal to 10 times the common logarithm of the power ratio.
Decibels are a unit of measure used to describe how loud a sound is. Now, I₀ is the intensity of threshold sound, which is sound that can barely be perceived by the human ear.
The loudness of a sound, in decibels, with intensity I is given by;
dB = 10 log₁₀(I/I₀)
We are given the intensity of a cat’s purr as I = 320I₀
Thus;
dB = 10 log₁₀(320I₀/I₀)
dB = 10 log₁₀(320)
dB = 25.05 ≈ 25
Read more about Decibel Level at; https://brainly.com/question/26209360
#SPJ1
use the second derivative test to classify the relative extrema if the test applies
Answer
The answer is:
[tex](x,f(x))=(0,256)[/tex]SOLUTION
Problem Statement
The question gives us a polynomial expression and we are asked to find the relative maxima using the second derivative test.
The function given is:
[tex](3x^2+16)^2[/tex]Method
To find the relative maxima, there are some steps to perform.
1. Find the first derivative of the function
2. Equate the first derivative to zero and solve for x.
3. Find the second derivative of the function.
4. Apply the second derivative test:
This test says:
[tex]\begin{gathered} \text{ If }a\text{ is one of the roots of the equation from the first derivative, then,} \\ f^{\doubleprime}(a)>0\to\text{There is a relative minimum} \\ f^{\doubleprime}(a)<0\to\text{There is a relative maximum} \end{gathered}[/tex]5. Find the Relative Minimum
Implementation
1. Find the first derivative of the function
[tex]\begin{gathered} f(x)=(3x^2+16)^2 \\ \text{Taking the first derivative of both sides, we have:} \\ f^{\prime}(x)=6x\times2(3x^2+16) \\ f^{\prime}(x)=12x(3x^2+16) \end{gathered}[/tex]2. Equate the first derivative to zero and solve for x.
[tex]\begin{gathered} f^{\prime}(x)=12x(3x^2+16)=0 \\ \text{This implies that,} \\ 12x=0\text{ OR }3x^2+16=0 \\ \therefore x=0\text{ ONLY} \\ \\ \text{Because }3x^2+16=0\text{ has NO REAL Solutions} \end{gathered}[/tex]This implies that there is ONLY ONE turning point/stationary point at x = 0
3. Find the second derivative of the function:
[tex]\begin{gathered} f^{\prime}(x)=12x(3x^2+16) \\ f^{\doubleprime}(x)=12(3x^2+16)+12x(6x) \\ f^{\doubleprime}(x)=36x^2+192+72x^2 \\ \therefore f^{\doubleprime}(x)=108x^2+192 \end{gathered}[/tex]4. Apply the second derivative test:
[tex]\begin{gathered} f^{\doubleprime}(x)=108x^2+192 \\ a=0,\text{ which is the root of the first derivative }f^{\prime}(x) \\ f^{\doubleprime}(a)=f^{\doubleprime}(0)=108(0)^2+192 \\ f^{\doubleprime}(0)=192>0 \\ \\ By\text{ the second derivative test,} \\ f^{\doubleprime}(0)>0,\text{ thus, there exists a relative minimum at }x=0\text{ } \\ \\ \text{ Thus, we can find the relative minimum when we substitute }x=0\text{ into the function }f(x) \end{gathered}[/tex]5. Find the Relative Minimum:
[tex]\begin{gathered} f(x)=(3x^2+16)^2 \\ \text{substitute }x=0\text{ into the function} \\ f(0)=(3(0)^2+16)^2 \\ f(0)=16^2=256 \\ \\ \text{Thus, the minimum value of the function }f(x)\text{ is }256 \\ \\ \text{The coordinate for the relative minimum for the function }(3x^2+16)^2\text{ is:} \\ \mleft(x,f\mleft(x\mright)\mright)=\mleft(0,f\mleft(0\mright)\mright) \\ \text{But }f(0)=256 \\ \\ \therefore(x,f(x))=(0,256) \end{gathered}[/tex]Since the function has ONLY ONE turning point, and the turning point is a minimum value, then THERE EXISTS NO MAXIMUM VALUE
Final Answer
The answer is:
[tex](x,f(x))=(0,256)[/tex]
How do I find the selling price if a store pays 3$ for a magazine. The markup is 5%
We need to find the selling price of a magazine. We know that the store pays $3 for it, and the markup is 5%.
So, we need to add 5% of the initial price to that initial price.
First, let's find:
[tex]5\%\text{ of }\$3=5\%\cdot\$3=\frac{5}{100}\cdot\$3=\frac{\$15}{100}=\$0.15[/tex]Now, adding the previous result to the initial price, we obtain:
[tex]\$3+\$0.15=\$3.15[/tex]Therefore, the selling price is $3.15.
x + 4y = 4 2x + 4y = 8x=4y=-2
x + 4y = 4
2x + 4y = 8
x=4
y=-2
we know that
If a ordered pair is a solution of a equation, then the ordered pair must satisfy the equation
we have the ordered pair (4,-2)
Verify if the ordered pair is a solution of the given equations
Equation 1
x+4y=4
substitute the value of x and the value of y in the given equation
(4)+4(-2)=4
4-8=4
-4=4 ------> is not true
the ordered pair is not a solution of the equation
Equation 2
2x + 4y = 8
substitute the value of x and the value of y in the given equation
2(4)+4(-2)=8
8-8=8
0=8 -----> is not true
the ordered pair is not a solution of the equation
Solve p3 = −512.
p = ±8
p = −8
p = ±23
p = −23
Answer:
B. p = −8
Step-by-step explanation:
Hope this helps you on whatever your doing. :))
if its incorrect, please let me know.
The solution is, the value is, p = −8.
What is multiplication?In mathematics, multiplication is a method of finding the product of two or more numbers. It is one of the basic arithmetic operations, that we use in everyday life.
here, we have,
given that,
p^3 = −512.
so, we know, p^3 = p*p*p
and, 512 = 8*8*8
now, we get,
p^3 = - 8*8*8
so, solving we get,
p = -8
Hence, The solution is, the value is, p = −8.
To learn more on multiplication click:
brainly.com/question/5992872
#SPJ2
write the expression using exponents 7•7•7•7•7•7• (–3)•(–3)•(–3)•(–3)
We have the number 7 multiplying itself 6 times, and the number (-3) multiplying itself 5 times, so writing the expression using exponents, we have:
[tex]\begin{gathered} 7\cdot7\cdot7\cdot7\cdot7\cdot7=7^6 \\ (-3)\cdot(-3)\cdot(-3)\cdot(-3)\cdot(-3)=(-3)^5 \\ \\ 7\cdot7\cdot7\cdot7\cdot7\cdot7\cdot(-3)\cdot(-3)\cdot(-3)\cdot(-3)\cdot(-3)=7^6\cdot(-3)^5 \end{gathered}[/tex]So the final expression is 7^6 * (-3)^5
Skis are listed by a manufacturer for $850, less trade discounts of 35% and 18%. What further rate of discount should be given to bring the net price to $446?
The Solution:
The listing price of the Skis by a manufacturer is $850.
A trade discount of 35% was allowed.
[tex]\begin{gathered} 35\text{ \% of \$850=0.35}\times850=\text{ \$297.50} \\ \text{Price}=850-297.50=\text{ \$552.50} \end{gathered}[/tex]Allowing an extra discount of 18%, we get
[tex]\begin{gathered} 18\text{ \% of \$}552.50=0.18\times552.50=\text{ \$99.45} \\ \text{Price}=552.50-99.45=\text{ \$453.05} \end{gathered}[/tex]We are required to find what further rate of discount should be given to bring the net price to $446.00
[tex]\begin{gathered} 453.05-446.00=7.05 \\ To\text{ find the required percentage of discount, we have} \\ \frac{7.05}{453.05}\times100=0.0155612\times100=1.55612\approx1.56\text{\%} \end{gathered}[/tex]Therefore, the correct answer is 1.56%
What is the value of sinθ given that (3, −7) is a point on the terminal side of θ?
Solution
[tex]\begin{gathered} \text{ using pythagoras theorem} \\ \\ OB=\sqrt{OA^2+AB^2}=\sqrt{3^2+7^2}=\sqrt{58} \\ \\ \Rightarrow\sin\theta=\frac{AB}{OB}=-\frac{7}{\sqrt{58}}=-\frac{7\sqrt{58}}{58} \end{gathered}[/tex]are f(x) and g(x) inverse functions across the domain (5, + infinity)
Given:
[tex]\begin{gathered} F(x)=\sqrt{x-5}+4 \\ G(x)=(x-4)^2+5 \end{gathered}[/tex]Required:
Find F(x) and G(x) are inverse functions or not.
Explanation:
Given that
[tex]\begin{gathered} F(x)=\sqrt{x-5}+4 \\ G(x)=(x-4)^{2}+5 \end{gathered}[/tex]Let
[tex]F(x)=y[/tex][tex]\begin{gathered} y=\sqrt{x-5}+4 \\ y-4=\sqrt{x-5} \end{gathered}[/tex]Take the square on both sides.
[tex](y-4)^2=x-5[/tex]Interchange x and y as:
[tex]\begin{gathered} (x-4)^2=y-5 \\ y=(x-4)^2+5 \end{gathered}[/tex]Substitute y = G(x)
[tex]G(x)=(x-4)^2+5[/tex]This is the G(x) function.
So F(x) and G(x) are inverse functions.
[tex]\begin{gathered} G(x)-5=(x-4)^2 \\ \sqrt{G(x)-5}=x-4 \\ x=\sqrt{G(x)-5}+4 \end{gathered}[/tex]Final Answer:
Option A is the correct answer.
John recently purchased $4,106.00 worth of a stock that is expected to grow in value by 8% each year for the next ten years.Assuming this growth forecast holds, which function will show the value of John's stock in tyears?A(t) = 1.08(54,106)A(O) = 54,106(1.1)A(0) = 54,106(1.08)A(t) = $4,106(1.08)
The exponential growth formula:
[tex]A(t)=A_0(1+r)^t[/tex]Given:
[tex]\begin{gathered} A_0=\text{ \$4106} \\ t=10yrs \\ r=8\%=\frac{8}{100}=0.08 \end{gathered}[/tex]Therefore,
[tex]A(t)=4106(1+0.08)^t=4106(1.08)^t[/tex]Hence, the answer is
[tex]A(t)=\text{ \$}4106(1.08)^t[/tex]Find the sum of the first nine terms of the geometric series 1 – 3 + 9 - 27+....
Hello there. To solve this question, we'll have to remember some properties about geometric series.
Given that we want the sum of
[tex]1-3+9-27...[/tex]First, we find the general term of this series:
Notice they are all powers of 3, namely
[tex]\begin{gathered} 1=3^0 \\ 3=3^1 \\ 9=3^2 \\ 27=3^3 \\ \vdots \end{gathered}[/tex]But this is an alternating series, hence the general term is given by:
[tex]a_n=\left(-3\right)^{n-1}[/tex]Since we just want the sum of the first 9 terms of this geometric series, we apply the formula:
[tex]S_n=\frac{a_1\cdot\left(1-q^n\right?}{1-q}[/tex]Where q is the ratio between two consecutive terms of the series.
We find q as follows:
[tex]q=\frac{a_2}{a_1}=\frac{\left(-3\right)^{2-1}}{\left(-3\right)^{1-1}}=\frac{-3}{1}=-3[/tex]Then we plug n = 9 in the formula, such that:
[tex]S_9=\frac{1\cdot\left(1-\left(-3\right)^9\right?}{1-\left(-3\right)}=\frac{1-\left(-19683\right)}{1+3}=\frac{19684}{4}[/tex]Simplify the fraction by a factor of 4
[tex]S_9=4921[/tex]This is the sum of the nine first terms of this geometric series and it is the answer contained in the second option.
Help me please I paid for the tutor Version of this app and it can’t fine me a tutor like I just paid 100 dollars for nothing
The Solution.
The function is increasing on the interval below:
[tex](-2.5,1)[/tex]The function is decreasing on the intervals below:
[tex](-\infty,-2.5)\cup(1,\infty)[/tex]If A and B are two random events with probabilities of P(A) = 4/9, P(B) = 2/9, P(A ∩ B) = 1/9, calculate P(B|A).a.1/4b.3/4c. 1/2d.1
Answer:
A. 1/4.
Explanation:
Given two random events A and B:
[tex]\begin{gathered} P(B|A)=\frac{P(B\cap A)}{P(A)} \\ P(B\cap A)=P(A\cap B) \end{gathered}[/tex]Substitute the given values:
[tex]P(B|A)=\frac{\frac{1}{9}}{\frac{4}{9}}=\frac{1}{9}\div\frac{4}{9}=\frac{1}{9}\times\frac{9}{4}=\frac{1}{4}[/tex]The value of P(B|A) is 1/4.
what number is divisible by 5 ? 86,764,670,or27
The number divisible by 5 is 670.
Numbers divisible by 5 have their last digits as 0 or 5
Answer : 670
One Sunday night, the Celluloid Cinema sold $ 1,585.75 in tickets. If the theater sold a children's ticket for $ 7.7S and an adult ticket for $ 10.25, a) write an equation to represent this situation. b) If the theater sold 75 children's tickets, solve your equation to find the number of adult tickets.
Answer:
98 adult tickets
Explanation:
Part A
Let the number of children's ticket sold = c
Let the number of adult's ticket sold = a
Cost of a children's ticket = $7.75
Cost of an adult's ticket = $10.25
Total income from ticket sales = $1,585.75
An equation to represent this situation is:
[tex]7.75c+10.25a=1585.75[/tex]Part B
If the number of children's ticket sold, c = 75
Then:
[tex]\begin{gathered} 7.75c+10.25a=1585.75 \\ 7.75(75)+10.25a=1585.75 \\ 581.25+10.25a=1585.75 \\ 10.25a=1585.75-581.25 \\ 10.25a=1004.50 \\ \frac{10.25a}{10.25}=\frac{1004.50}{10.25} \\ a=98 \end{gathered}[/tex]The number of adult tickets sold by the cinema is 98.
the output is 9 less than 5 times the input"
Let the output is y and the input is x, then
output is means y =
9 less than 5 times input means 9 less than 5x
Then
y = 5x - 9
Kepler's third law of planetary motion states that the square of the time required for a planet to make one revolution about the sun varies directly as the cube of the average distance of the planet from the sun. If you assume that Jupiter is 5.2 times as far from the sun as is the earth, find the approximate revolution time for Jupiter in years.
Show work pls ;-;
By applying Kepler's third law of planetary motion, the approximate revolution time for Jupiter is equal to 12 years.
What is Kepler's third law?Mathematically, Kepler's third law of planetary motion is given by this mathematical expression:
T² = a³
Where:
T represents the orbital period.a represents the semi-major axis.Note: Earth has 1 astronomical unit (AU) in 1 year of time.
For this direct variation, the value of the constant of proportionality (k) is given by:
T² = ka³
k = T²/a³
k = 1²/1³
k = 1.
When the semi-major axis or the distance of Jupiter from Sun is 5.2, we have;
T² = ka³
T² = 1 × 5.2³
T² = 140.608
T = √140.608
T = 11.858 ≈ 12 years.
Read more on Kepler's third law here: https://brainly.com/question/15691974
#SPJ1
Choose the correct translation for the following statement.It must exceed seven.Ox<7Ox57Ox>7Ox27
Solution:
Given that a value or quantity must not exceed ten, let x represent the value or quantity.
Since it must not exceed 10, this implies that
[tex]x\leq10[/tex]The second option is the correct answer.
The graph shows the depth, y, in meters, of a shark from the surface of an ocean for a certain amount of time, x, in minutes:A graph is titled Distance Vs. Time is shown. The x axis is labeled Time in minutes and shows numbers 0, 1, 2, 3, 4, 5. The y axis is labeled Distance from Ocean Surface in meters. A straight line joins the points C at ordered pair 0,66, B at ordered pair 1, 110, A at ordered pair 2, 154, and the ordered pair 3, 198.Part A: Describe how you can use similar triangles to explain why the slope of the graph between points A and B is the same as the slope of the graph between points A and C. (4 points)Part B: What are the initial value and slope of the graph, and what do they represent? (
We are given a graph that shows the depth in meters (y) as a function of the time in minutes (x).
Part A:
Points A, B, and their projection in the point (2, 110) form a similar triangle with the triangle formed by points A, C, and the point (2, 66).
Determine if the proportion is true 1/6= 3/18 Proportion is not true Proportion is true
Question: Determine if the proportion is true 1/6= 3/18
Solution:
we have the following equation that it may be true or false:
[tex]\frac{1}{6}\text{ = }\frac{3}{18}[/tex]But, the above equation is equivalent to:
[tex]1\text{ x 18 = 3 x 6}[/tex]But 1x 18 = 18, and 3x 6 = 18 so the above equation is equivalent to
[tex]18\text{ = 18}[/tex]The above equality always is true, so we can conclude that the proportion is true.