Question

若a+b分之a-b=4,求代数式a+b分之5(a-b)-2(a-b)分之a+b的值

Answer 1

答：

(a-b)/(a+b)=4

(a+b)/(a-b)=1/4

5(a-b)/(a+b)-(a+b)/[2(a-b)]

=5*4-(1/4)*(1/2)

=20-1/8

159/8