Question

(1)x²+y²-2xy分之xy （分开的） 乘 3x²分之x-y (2)(x-y分之x

Answer 1

(1)x²+y²-2xy分之xy （ 分开的） 乘 3x²分之x-y

=xy/(x-y)²×(x-y)/3x²

=y/3x(x-y)

=y/(3x²-3xy)

(2)(x-y分之x - x-y分之2y) 乘 x-2y分之xy 除以（x分之1+y分之1）

=(x-2y)/(x-y)×xy/(x-2y)×xy/(x+y)

=x²y²/(x-y)(x+y)

=x²y²/(x²-y²)