解(1)：最简公分母是6(x+5)
3分之x=x/3
=2x(x+5)/[6(x+5)]
6分之1-x=(1-x)/6
=(1-x)(x+5)/[6(x+5)]
x+5分之x平方-x=(x²-x)/(x+5)
=6x(x-1)/[6(x-5)]
(2)：最简公分母是3xy²
3y平方分之(x-y)(x-2)=(x-y)(x-2)/(3y²)
=x(x-y)(x-2)/(3xy²)
3xy分之(x-y)(2-x)=(x-y)(2-x)/(3xy)
=y(x-y)(2-x)/(3xy²)