Tìm x biết: a) (x^2 - x + 1)(x + 1) - x^3 - 3x = 1; b) (x^2 - 5)(x + 2) + 5x = 2x^2 + 7; c) (x + 2)(x^2 - 2x + 4) - x(x^2 + 5) = 2

Bài 1: Tìm x biết:
a) (x^2 - x + 1)(x + 1) - x^3 - 3x = 1
b) (x^2 - 5)(x + 2) + 5x = 2x^2 + 7
c) (x + 2)(x^2 - 2x + 4) - x(x^2 + 5) = 2
Bài 2:
a) (a + b)(a - b) = a^2 - b^2
b) (x - y)(x^2 + xy + y^2) = x^3 - y^3
c) (x - 1)(x^2 + x + 1) = x^3 - 1
d) (x + y)^3 = x^3 + 3x^2y + 3xy^2 + y^3