Question

-(16x^2 y^3)/(20xy^4) , (x^2-9)/（x-3）， (x^2-2x)/(2y-xy), (m^2-2m+1)/(1-m^2）

速答，谢谢了！！

Answer 1

-(16x^2 y^3)/(20xy^4)=-4x/(5y)
.
(x^2-9)/（x-3）=x+3
.
(x^2-2x)/(2y-xy)=x(x-2)/[y(2-x)]=-x/y
.
(m^2-2m+1)/(1-m^2）=(m-1)²/[(1-m)(1+m)]=(1-m)/(1+m)

Answer 2

1) -(16x^2 y^3)/(20xy^4) =-4x/5y
2)(x^2-9)/（x-3）=(x+3)(x-3)/(x-3)=x+3
3)(x^2-2x)/(2y-xy), =【x(x-2)】/【y(2-x)】=-x/y
4) (m^2-2m+1)/(1-m^2）=(m-1)²/【(1-m)(1+m）】=（1-m）/(1+m)