已知3x =2y 求x/x+y+y/x-y-y²/x²-y²
问题描述：
已知3x =2y 求x/x+y+y/x-y-y²/x²-y²
答
3x =2y
∴y=3x/2
x/x+y+y/x-y-y²/x²-y²
=[x(x-y)+y(x+y)-y²]/(x+y)(x-y)
=x²/(x²-y²)
=x²/(x²-9x²/4)
=-4/5