题目应该是x³－4xy²－2x²y＋8y³
=(x³＋8y³)－(4xy²＋2x²y)
=(x＋2y)(x²－2xy＋4y²)－2xy(x＋2y)[x³＋8y³用立方和公式分解,8y³=(2y)³]
=(x＋2y)(x²－2xy＋4y²－2xy)
=(x＋2y)(x²－4xy＋4y²)
=(x＋2y)(x－2y)²
不懂还可问,满意请及时采纳!o(∩_∩)o