化简求值:(x²-2y²)(x+2y)-2xy(x-y)其中x=-2,y=-½
问题描述:
化简求值:(x²-2y²)(x+2y)-2xy(x-y)其中x=-2,y=-½
答
数学之美团为你解答
原式 = (x³+2x²y-2xy²-4y³) - 2x²y+2xy²
= x³ - 4y³
= (-2)³ - 4×(-1/2)³
= - 15/2