化简分式 1.x-y/(x-y)^3 2.x^2+x/x^2-1 3.x^2-9/x^2-6x+9

问题描述:

化简分式 1.x-y/(x-y)^3 2.x^2+x/x^2-1 3.x^2-9/x^2-6x+9

1.x-y/(x-y)^3
=1/(x-y)^2
2.x^2+x/x^2-1
=x(x+1)/(x+1)(x-1)
=x/(x-1)
3.x^2-9/x^2-6x+9
=(x+3)(x-3)/(x-3)^2
=(x+3)/(x-3)