Question

Suppose y varies directly with x. When

xis -2, y is 10. Write the equation that
relates x and y.

Answer 1

`y=-5x`

Explanation:

we know that

A relationship between two variables, x, and y, represent a direct variation if it can be expressed in the form
`y/x=k` or
`y=kx`

In this problem we have

For x=-2, y=10

Find the value of the constant of proportionality k

`k=y/x`

substitute the value of x and the value of y

`k=10/-2=-5`

so

The linear equation is equal to

`y=-5x`