Tìm x biết: a) (x + 4)(x^2 - 4x + 16) - x(x - 5)(x + 5) = 264, b) (x - 2)^2 - (x - 2)(x^2 + 2x + 4) + 6(x - 2)(x + 2) = 60

Tìm x, biết:
a) (x + 4)(x^2 - 4x + 16) - x(x - 5)(x + 5) = 264
b) (x - 2)^2 - (x - 2)(x^2 + 2x + 4) + 6(x - 2)(x + 2) = 60