Question

Which of the following equations is an example of inverse variation between variables x and y?

A. y = x + 7
B. y = 7x
C. y = x/7
D. y = 7/x

Answer 1

D.
`y=(7)/(x)`

Explanation:

Let y varies inversely with x.

Then we can write the variation equation:

`y\propto (1)/(x)`

We introduce the constant of proportionality, k and obtain the inverse variation equation:

`y=(k)/(x)`

From the given options, the only equation in this form is

`y=(7)/(x)`

In this case, k=7 is the constant of proportionality or constant of variation.