Find the value of x when a=1, b=2, y= 3 by using general formula After replace number in a, b, y we have 3 = 1ax^2 - 2x - 12 x^2 - 2x -15 = 0 x^2 - 5x + 3x -15 = 0 (x^2 - 5x) + (3x -15) = 0 x*(x - 5) + 3*(x - 5) = 0 (x - 5)*(x + 3) = 0 x - 5 = 0 or x + 3 = 0 x=5 or x=-3