计算题：1.1/a+1—2/1-a² 2.x/x-y—y/x+y

题目

计算题：1.1/a+1—2/1-a² 2.x/x-y—y/x+y

答案

原式=(a-1)/(a+1)(a-1)+2/(a+1)(a-1)
=(a-1+2)/(a+1)(a-1)
=(a+1)/(a+1)(a-1)
=1/(a-1)
原式=(x²+xy-xy+y²)/(x+y)(x-y)
=(x²+y²)/(x²-y²)