The equation is solved by proper methods: (1) (x + 6) 2-9 = 0; (2) x2-4x-2 = 0; (3) 3x2-8x + 4 = 0; (4) (X-2) = 5x (2-x)

The equation is solved by proper methods: (1) (x + 6) 2-9 = 0; (2) x2-4x-2 = 0; (3) 3x2-8x + 4 = 0; (4) (X-2) = 5x (2-x)

(1) From the original equation, we get (x + 6) 2 = 9, square root, x + 6 = ± 3, then x = - 6 ± 3, solve X1 = - 3, X2 = - 9; (2) from the original equation, we get x2-4x = 2, formula, we get x2-4x + 22 = 2 + 22, that is, (X-2) 2 = 6, square root, we get X-2 = ± 6, solve X1 = 2 + 6, X2 = 2-6; (3) from 3x2-8x + 4 = 0, a = 3