已知代数式a+b/a-b=2,那么代数式(3a+3b/5a-5b)-(3a-3b/2a+ab)
问题描述：
已知代数式a+b/a-b=2,那么代数式(3a+3b/5a-5b)-(3a-3b/2a+ab)
答
因为（a+b）/（a-b）=2，所以：（a-b）/（a+b）=1/2
(3a+3b）/（5a-5b)-(3a-3b）/2（a+b)
=3/5*（a+b）/（a-b）-3/2*（a-b）/（a+b）
=3/5*2-3/2*1/2
=6/5-3/4=3/4
答
题目打错了,最后应该是2b吧(3a+3b/5a-5b) = 3（a+b)/5(a-b) =3/5X(a+b/a-b) = 3/5x 2 = 6/5(3a-3b/2a+2b) = 3(a-b)/2(a+b ) = 3/2x(a-b/a+b) = 3/2x1/2 = 3/4所以(3a+3b/5a-5b)-(3a-3b/2a+2b) = 6/5-3/4 = 9/20 （小...