问题描述： 如图,M,N为线段如图,M、N为线段AB上两点,且AM:MB=1:3,AN：NB=5：7.若MN=2,求AB的长用方程的思想 1个回答 分类：数学 2014-10-09 问题解答： 我来补答 因为,AM/AB = AM:(AM+MB) = 1/(1+3) = 1/4 ,AN/AB = AN/(AN+NB) = 5/(5+7) = 5/12 ,所以,AM = (1/4)AB ,AN = (5/12)AB ；因为,MN = AN-AM = (5/12-1/4)AB = (1/6)AB ,所以,AB = 6MN = 12 . 展开全文阅读
