Question

两题初二数学题目 大家帮帮忙(x-y)乘x^2/x^2-y^2 a^2-a/a^2+2a+1÷a^2-a/a+1

Answer 1

(x-y)乘x^2/x^2-y^2 =x^2/(x+y)；

a^2-a/a^2+2a+1÷a^2-a/a+1

=a(a-1)/(a+1)^2*(a+1)/a(a-1)

=1/(a+1)