先化简,再求值x/x的平方-2xy+y平方乘x的平方-y的平方/x+y+(2x+2/x-y)-2其中x,y满足方程组x+2y=3,x-y=-5.

问题描述:

先化简,再求值x/x的平方-2xy+y平方乘x的平方-y的平方/x+y+(2x+2/x-y)-2其中x,y满足方程组x+2y=3,x-y=-5.

这个题目有点乱……如果理解成:[x/(x²-2xy+y²)]*[(x²-y²)/(x+y)]+(2x+2)/(x-y)-2则化简:=[x/(x-y)²]*[(x+y)*(x-y)/(x+y)]+(2x+2)/(x-y)-2=x/(x-y)+(2x+2)/(x-y)-2=[x+(2x+2)-2(x-y)]/(x-...