若a-b/a+b=4 则代数式2a﹣2b/a+b-4a+4b/3a-3b=
问题描述：
若a-b/a+b=4 则代数式2a﹣2b/a+b-4a+4b/3a-3b=
答
(a-b)/(a+b)=4
∴(a+b)/(a-b)=1/4
2a﹣2b/a+b-4a+4b/3a-3b
=2(a-b)/(a+b)-(a+b)/(a-b)*4/3
=2*4-1/4*4/3
=8-1/3
=23/3 7又2/3