Question

Solve the equation for y-value and choose whether it is a direct variation or inverse variation.

xy=7

a) y=7/x direct variation
b) y=x/7 direct variation
c) y=x/7 inverse variation
d) y=7/x inverse variation​

Answer 1

Given:

The equation is
`xy=7`.

To find:

Whether the given equation is a direct variation or inverse variable.

Solution:

Direct variation: y is directly proportional to x.

`y\propto x`

`y=kx`

Inverse variation: y is inversely proportional to x.

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

`y=(k)/(x)`

Where, k is the constant of proportionality.

We have,

`xy=7`

Divide both sides by x.

`y=(7)/(x)`

It is in the form of inverse variation.

Since
`y=(7)/(x)` and it is inverse variation, therefore the correct option is (d).