通分:(1)1/a+1,3/1-a,5/a^2-1(2)a/a-b,b/a^2-b^2,c/a+b^2(3)a/a^2-4,a-1/a-2,a+2/a^2-4a+4
问题描述:
通分:
(1)1/a+1,3/1-a,5/a^2-1
(2)a/a-b,b/a^2-b^2,c/a+b^2
(3)a/a^2-4,a-1/a-2,a+2/a^2-4a+4
答
(1)1/a+1=(A-1)/(A方-1)3/1-a=-(3A+3)/(A方-1)5/a^2-1 (2)a/a-b=[A(A+B)(A+B方]/[(A方-B方)(A+B方)]b/a^2-b^2=B(A+B方)/[(A方-B方)(A+B方)]c/a+b^2 =C(A方-B方)/[(A方-B方)(A+B方)](3)a/a^2-4=A(A-2)/[(A+2)(A-2)方]...