Hi, (1/3)y^2 + 12 = 5x substituting x = 3 (1/3)y^2 + 12 = 15 Multiplying each side of the equation by 3 y^2 +36 = 45 y^2 = 9 y = 3 checking our answer 9/3 + 12 = 3 + 12 = 15 = 5*3