Question

如图,a.b.c.d是直线l上顺次四点,且线段ac=5,bd=4,则线段ab-cd等于（ ）

Answer 1

设bc = x,有ab = ac - bc = 5 - x,cd = bd - bc = 4 - x,

ab - cd = (5 - x) - (4 - x) = 1