Giải phương trình: (9x^2 – 4x)(x + 1) = (3x + 2)(x^2 – 1).
Giải thích
(9x2 – 4x)(x + 1) = (3x + 2)(x2 – 1)
⇔ (3x + 2)(3x − 2)(x + 1) = (3x + 2)(x − 1)(x + 1)
⇔ (3x + 2)(3x −2 )(x + 1) − (3x + 2)(x − 1)(x + 1) = 0
⇔ (3x + 2)(x + 1)(3x – 2 – x + 1) = 0
⇔ (3x + 2)(x + 1)(2x − 1) = 0
⇔ x=−23x=−1x=12.