Question

How do you write the direct variation equation if f(x) = –18 when x = 3?

Answer 1

Direct variation function is `f(x)=-6x`

Explanation:

Direct variation equation is of type `f(x)=kx`

As we have `f(x)=-18`, when `x=3`, we have

`-18=k*3` i.e. `k=-18/3=-6`

Hence, direct variation function is `f(x)=-6x`