g(x) = x2 + 3x When g(x + 1) = (x + 1)^2 + 3(x + 1) = x2 + 1 + 2x + 3x + 3 = x2 + 5x + 4 g(x + 1) - g(x) = x2 + 5x + 8 - (x2 + 3x) = x2 + 5x + 4 - x2 -3x = 2x + 4 or 2(x + 4) = 2(x + 2)