x/y=2/3
所以y=3x/2
原式=[5y²-(x-2y)(x+2y)]/(x-2y)÷(x-3y)²/(x-2y)
=(9y²-x²)/(x-2y)*(x-2y)/(x-3y)²
=-(x+3y)(x-3y)/(x-2y)*(x-2y)/(x-3y)²
=-(x+3y)/(x-3y)
=-(x+3x/2)/(x-3x/2)
=5-(x+3x/2)/(x-3x/2)这一步的计算结果好像不是5啊对
采纳吧=-(x+3y)/(x-3y)
=-(x+3x/2)/(x-3x/2)这两部是怎么转换过来的？不是3x/2还要乘以三吗哦，对不起，是错了

x/y=2/3
所以y=3x/2

原式=[5y²-(x-2y)(x+2y)]/(x-2y)÷(x-3y)²/(x-2y)
=(9y²-x²)/(x-2y)*(x-2y)/(x-3y)²
=-(x+3y)(x-3y)/(x-2y)*(x-2y)/(x-3y)²
=-(x+3y)/(x-3y)
=-(x+9x/2)/(x-9x/2)
=11/7