y ∝x y= kx substitute x and y values 108= k x 9 because you want to find k on its own you divide both sides by 9 108 ÷ 9 = 12 So k = 9 Now that we have 12 we can use this to find y y = 12 x 8 You just simply times it because that's what y is so y= 96 when x=8 To find y when x= 7 you do 7 x 12 which is 84 So y= 84 when x= 7
