Question

已知a-b/a+b=3,求代数式2（a+b）/a-b-4（a-b)/3（a+b）的值

Answer 1

(a-b)/(a+b)=3 =>a-b=3a+3b =>4b=2a => a=2b≠0

=>2（a+b）/(a-b) - 4（a-b)/3（a+b）=2(3b)/(b) - 4(b)/3(3b) =6 - 4/9 =50/9..ans