Answer:
$X = $12y
Step-by-step explanation:
In this question, we are asked to give an expression to represent the amount of money charged to a man who stayed in a motel for a particular number of days.
Firstly, we need to know the amount of money charged per day. This is visible from
the question and it is equal to $y.
Secondly, the number of days/night stayed is 12 days. This means that the amount of money he was charged is 12 * y = $12y
Since the amount of money charged is equal to $x, the amount to pay can be expressed in terms of y and x to be
$X = $12y
![\bf \textit{equation of a circle}\\\\ (x- h)^2+(y- k)^2= r^2 \qquad center~~(\stackrel{}{ h},\stackrel{}{ k})\qquad \qquad radius=\stackrel{}{ r}\\\\ -------------------------------\\\\ (x-3)^2+(y+7)^2=64\implies [x-\stackrel{h}{3}]^2+[y-(\stackrel{k}{-7})]^2=\stackrel{r}{8^2} \\\\\\ center~(3,-7)\qquad radius=8](https://tex.z-dn.net/?f=%5Cbf%20%5Ctextit%7Bequation%20of%20a%20circle%7D%5C%5C%5C%5C%20%0A%28x-%20h%29%5E2%2B%28y-%20k%29%5E2%3D%20r%5E2%0A%5Cqquad%20%0Acenter~~%28%5Cstackrel%7B%7D%7B%20h%7D%2C%5Cstackrel%7B%7D%7B%20k%7D%29%5Cqquad%20%5Cqquad%20%0Aradius%3D%5Cstackrel%7B%7D%7B%20r%7D%5C%5C%5C%5C%0A-------------------------------%5C%5C%5C%5C%0A%28x-3%29%5E2%2B%28y%2B7%29%5E2%3D64%5Cimplies%20%5Bx-%5Cstackrel%7Bh%7D%7B3%7D%5D%5E2%2B%5By-%28%5Cstackrel%7Bk%7D%7B-7%7D%29%5D%5E2%3D%5Cstackrel%7Br%7D%7B8%5E2%7D%0A%5C%5C%5C%5C%5C%5C%0Acenter~%283%2C-7%29%5Cqquad%20radius%3D8)
so, the broadcast location and range is more or less like the picture below.
Multiplying fractions is just multiplying the numerators together and the denominators together.
![\sf\dfrac{4}{7}\times\dfrac{1}{4}\rightarrow\dfrac{4\times 1}{7\times 4}\rightarrow\dfrac{4}{28}\rightarrow\dfrac{1}{7}](https://tex.z-dn.net/?f=%5Csf%5Cdfrac%7B4%7D%7B7%7D%5Ctimes%5Cdfrac%7B1%7D%7B4%7D%5Crightarrow%5Cdfrac%7B4%5Ctimes%201%7D%7B7%5Ctimes%204%7D%5Crightarrow%5Cdfrac%7B4%7D%7B28%7D%5Crightarrow%5Cdfrac%7B1%7D%7B7%7D)
![\sf\dfrac{4}{7}\times\dfrac{1}{6}\rightarrow\dfrac{4\times 1}{7\times 6}\rightarrow\dfrac{4}{42}\rightarrow\dfrac{2}{21}](https://tex.z-dn.net/?f=%5Csf%5Cdfrac%7B4%7D%7B7%7D%5Ctimes%5Cdfrac%7B1%7D%7B6%7D%5Crightarrow%5Cdfrac%7B4%5Ctimes%201%7D%7B7%5Ctimes%206%7D%5Crightarrow%5Cdfrac%7B4%7D%7B42%7D%5Crightarrow%5Cdfrac%7B2%7D%7B21%7D)
To find out which one is bigger, we need a common denominator. The LCM of 7 and 21 is 21, so convert the first fraction into a denominator of 21. 7 goes into 21 three times, multiply this to the numerator and denominator:
![\sf\dfrac{1}{7}\rightarrow\dfrac{1\times 3}{7 \times 3}\rightarrow\dfrac{3}{21}](https://tex.z-dn.net/?f=%5Csf%5Cdfrac%7B1%7D%7B7%7D%5Crightarrow%5Cdfrac%7B1%5Ctimes%203%7D%7B7%20%5Ctimes%203%7D%5Crightarrow%5Cdfrac%7B3%7D%7B21%7D)
Now just compare the numerators to see which one is bigger.
![\sf\dfrac{3}{21}>\dfrac{2}{21}](https://tex.z-dn.net/?f=%5Csf%5Cdfrac%7B3%7D%7B21%7D%3E%5Cdfrac%7B2%7D%7B21%7D)
therefore,
3 boxes times 40 = 120 + 3 = 143
or 3 boxes times 43 = 129