a+b除以a-b=7,求2(a+b)除以a-b-a-b除以3(a+b)的值
问题描述：
a+b除以a-b=7,求2(a+b)除以a-b-a-b除以3(a+b)的值
答
当a≠b时
(a b)/(a-b)=7
a b=7(a-b)
2(a b)/(a-b)-(a-b)/3(a b)
=2×7(a-b)÷(a-b)-(a-b)/[3×7(a-b)]
=14-1/21
=13又20/21
祝你学习进步
答
(A+B)/(A-B)=2说明A-B和A+B的值均不为零
那么(A+B)/[2(A+B)]=1/2
3(A-B)/(A+B)=3*(1/2)=3/2
所以结果(A+B)/[2(A+B)]-3(A-B)/(A+B)=-1