若a≠b,数列a,x1,x2,b和数列a,y1,y2,y3,b都是等差数列,则 x2−x1y2−y1=(  ) A.23 B.34 C.1 D.43

问题描述:

若a≠b,数列a,x1,x2,b和数列a,y1,y2,y3,b都是等差数列,则 

x2x1
y2y1
=(  )
A.
2
3

B.
3
4

C. 1
D.
4
3

∵a、x1、x2、b成等差数列
∴x2-x1=

1
3
(b-a)
∵a,y1,y2,y3,b都是等差数列,
∴y2-y1=
1
4
(b-a)
x2x1
y2y1
=
4
3

故选:D.