Question

If y= 12 when x = 18, find xwhen y=-16.

Answer 1

ANSWER

x = -24

EXPLANATION

We have that y = 12 when x = 18.

To solve this we have to use the ratio of y to x.

We have that y : x is:

12 : 18

We also have:

-16 : x

Since the ratios are equal to y : x, we have:

$\begin{gathered} 12\text{ : 18 = -16 : x} \\ \Rightarrow\text{ }\frac{12}{18}\text{ = }\frac{-16}{x} \\ \text{Cross}-mu\text{ltiply:} \\ 12\cdot\text{ x = -16 }\cdot\text{ 18} \\ x\text{ = }\frac{-16\cdot\text{ 18}}{12} \\ x\text{ = -24} \end{gathered}$

That is the value of x.