X(X - 2)(X + 2) - (X + 2)(X2 - 2X + 4) = 4⇔ X(X2 - 4) - (X3 + 8) = 4⇔ X3 - 4X - X3 - 8 - 4 = 0⇔ -4X = 12⇔ X = -3SUY RA X = -3VẬY X = -3

Câu 2:a.b.x(x - 2)(x + 2) - (x + 2)(x

²

- 2x + 4) = 4⇔ x(x

²

- 4) - (x

³

+ 8) = 4⇔ x

³

- 4x - x

³

- 8 - 4 = 0⇔ -4x = 12⇔ x = -3Suy ra x = -3Vậy x = -3