化简[(xx-2xy+yy)(xx-2xy+yy)-xxxx+yyyy]÷(xx-yy)(xx-yy)的结果是
问题描述:
化简[(xx-2xy+yy)(xx-2xy+yy)-xxxx+yyyy]÷(xx-yy)(xx-yy)的结果是
答
原式=[(x-y)²(x-y)²-(x²+y²)(x²-y²)]/(x²-y²)²=[(x²-2xy+y²)-(x²+y²)]/(x²-y²)=-2xy/(x²-y²)