(2a+2)/(a-1)÷(a+1)+(a²-1)/(a²-2a+1)
=2(a+1)/(a-1)÷(a+1)+(a+1)(a-1)/(a-1)²
=2/(a-1)+(a+1)/(a-1)
=(a+3)/(a-1)
化简的结果就是上面的
a=1不可以哦,因为此时分母为0是无意义的