已知:ab=cd=ef=23,求值:(1)a+cb+d;(2)2a−c+3e2b−d+3f.

问题描述:

已知:

a
b
=
c
d
=
e
f
=
2
3
,求值:
(1)
a+c
b+d
;(2)
2a−c+3e
2b−d+3f

(1)∵

a
b
=
c
d
=
e
f
=
2
3

∴原式=
2
3

(2)∵
a
b
=
c
d
=
e
f
=
2
3

2a
2b
=
−c
−d
=
3e
3f

∴原式=
2
3

答案解析:根据已知比例式,利用比例的等比性质直接求解即可.
考试点:比例的性质.
知识点:考查了等比的性质.如果
a
b
c
d
=…=
m
n
(b+d+…n≠0),
a+c+…+m
b+d+…+n
=
a
b