y varies directly with x. if y=-4 when x=2 find y when x=-6
This means that
y = kx where k is a constant
sub in x=2, y=-4 to find k
-4=k*2
k= -2
so
y= -2x
now sub in x=-6 to get the corresponding y value
y = -2*-6
y= 12
When x=-6 y=12
