1/(-6ab^2)=-a/6a^2b^2.

(2)1(a+b) 2 = (a-b)/(a+b) 2 (a-b

3/(a^2-b^2)=3(a+b)/(a+b)^2(a-b).

⑶(a- 1)/(a^2+2a+ 1)=(a- 1)^2/(a+ 1)^2(a- 1)

6/(a^2- 1)=6(a+ 1)/(a+ 1)^2(a- 1).

⑷b/3a^2c^2= 10b^3/30a^2b^2c^2

c/2ab= 15abc^3/30a^2b^2c^2

a/5b^2c=6a^3c/30a^2b^2c^2.