化简求值y/(x-y)+y³/(x³-2x²y+xy²)÷(xy+y²)/(y²-x²)
问题描述：
化简求值y/(x-y)+y³/(x³-2x²y+xy²)÷(xy+y²)/(y²-x²)
其中x=2/3 y=-3
答
y/(x-y)+y³/(x³-2x²y+xy²)÷(xy+y²)/(y²-x²)
=y/(x-y)+y³/x（x-y)(x-y)÷[y(x+y)/(y-x)(y+x)]
=y/(x-y)-y³/x（x-y)²÷[y/(x-y)]
=y/(x-y)-y²/x（x-y)
=y(x-y)/x（x-y)
=y/x
= - 9/2
很高兴为你答疑,