Question

The variables x=-3 and y=9 varies directly. How do you write an equation that relates the variables and find y when x=8?

Answer 1

`y=-3x`

`24`

Explanation:

`y`" and "x vary directly#

`:.y propx`

`=>y=kx`

we are given

`x=-3,y=9`

`:.9=-3k`

`=>k=-3`

`:.y=-3x`

whe `x=8`

`y=-3xx8=-24`