Giải phương trình: a) (2x + 1)^2 - 4(x + 2)^2 = 9; b) (3x - 1)^2 + 2(x + 3)^2 + 11(x + 1)(1 - x) = 6; c) (x + 1)^3 - x^2(x + 3) = 2

a) (2x + 1)2 - 4(x + 2)2 = 9
b) (3x - 1)2 + 2(x + 3)2 + 11(x + 1)(1 - x) = 6
c) (x + 1)3 - x2 (x + 3) = 2
d) (x - 2)3 - x(x + 1)(x - 1) + 6x2 = 5
e) (x - 3)(x2 + 3x + 9) - x(x + 4)(x - 4) = 5
g) (x - 2)3 - (x + 5)(x2 - 5x + 25) + 6x2 = 11