Question

计算：2-x/x-1除以(x+1-3/x-1) 计算：(a-a/a+1)除以a^2-2a/a^2-4乘以1/a+2

Answer 1

=(2-x)/(x-1)×(x-1)/[(x²-1-3)

=-(x-2)/(x-1)×(x-1)/(x+2)(x-2)

=-1/(x+2)

(a-a/a+1)除以a^2-2a/a^2-4乘以1/a+2

=(a²+a-a)/(a+1)×a(a-2)/(a+2)(a-2)×1/(a+2)

=a²/(a+1)×a/(a+2)×1/(a+2)

=a³/(a+1)(a+2)²