通分5道约分10道

5X/25x^2=1/5x,
(9ab^2+6abc)/3a^2b
=3ab(3b+2c)/3a^2b
=(3b+2c)/a
(9a^2+6ab+b^2)/(3a+b)
=(3a+b)^2/(3a+b)
=3a+b
(x^2-36)/(2x+12)
=(x+6)(x-6)/2(x+6)
=(x-6)/2
5)
x/3y=2xy/6y^2,
3x/2y^2=9x/6y^2
6)
6c/a^2b=18c/3a^2b,
c/3ab=ac/3a^2b,
7)
x/(2x+2y)=(x+y)/2(x+y)^2,
xy/(x+y)^2=2xy/2(x+y)^2,
8)
2mn/(4m^2-9)=2mn/(2m+3)(2m-3),
(2m-3)/(2m+3)=(2m-3)^2/(2m+3)(2m-3)

百度一下，你就知道