约分:x-1/x^2-2x+1;a^2-4/a^2-4a+4

问题描述:

约分:x-1/x^2-2x+1;a^2-4/a^2-4a+4

1.(x-1)/(x-1)^2=1/(x-1)
2.(a^2-4)/(a-2)^2=(a-2)(a+2)/(a-2)^2=(a+2)/(a-2)