math 2 1

a + b 2 a b 2 a b x 2 + 4 x + 4 = 0 x = - b ± b 2 - 4 a c 2 a z x + y x 2 4 x 4 0 x ± b 2 b 2 4 a c 2 a A x y z w 1 t x x x 1 t 1 x x 1 t 1 x 1 t x x x + a / b