Question

顺便右上角的那个题求最简公分母

Answer 1

1/（ab^2)=3ac/(3a^2b^2c),

1/(3a^2c)=b^2/(3a^2b^2c).

1/(xy^2)=x/(xy)^2,

1/x^2y)=y/(xy)^2.

1/(a^2-1)=a/[a(a+1)(a-1)],

1/(a^2-a)=(a+1)/[a(a+1)(a-1)].

2/(9-3a)=-2(a+3)/[3(a-3)(a+3)]

(a-1)/(a^2-9)=3(a-1)/[3(a-3)(a+3)].