if y = -4 when x=10 find y when x=2

Answer 1

if x and y vary directly

then

y=kx

-4=k(10)

k =-4/10 =-.4

y =-.4x

y =-.4(2) =-.8

y = -.8 when x = 2

but if x and y vary inversely

then

y =k/x

-4 =k/10

k=-40

y =-40/x

y =-40/2

y =-20 when x = 2