F.4 quadratic equation 3條求解

1) (x + 1)² + 3(x + 1) – 4 = 0[(x + 1) – 1][(x + 1) + 4] = 0 x(x + 5) = 0 x= 0 or x = - 5 2) (4 - x)² - 5(4 - x) – 14 = 0[(4 – x) – 7][(4 – x) + 2] = 0 (- x – 3)(6 – x) = 0 x= - 3 or x = 6 3) (x + 2)² - 81x² = 0[(x + 2) – 9x][(x + 2) + 9x] = 0 (2 – 8x)(2 + 10x) = 0 x= 1/4 or x = - 1/5