Question

Find direct variation if y=-6 when x=9, find x when y=-3

Answer 1

direct variation

y =kx

substitute y and x to find k

-6 = k(9)

divide by 9

-6/9 =k

k = -2/3

y = -2/3 x

now substitute y =-3 to find x

-3 = -2/3 x

multiply by -3/2 on each side

-3 * -3/2 = -3/2 * -2/3 x

9/2 = x