Question

How do you write a direct variation equation that relates x and y if y=-8 when x= 2, and how do you find y when x=32?

Answer 1

A direct variation equation is of the form
`y = mx` for some constant value `m`

We are told that `(x,y) = (2,-8)` satisfies the required equation, so
`(-8) = m(2)`
`rarr m= (-4)`
and the direct variation equation is
`y = (-4)x`

When `x=32`
`y = (-4)(32) = (-128)`