若ab=20,bc=10,则a+bb+c的值为( ) A.1121 B.2111 C.11021 D.21011
问题描述:
若
=20,a b
=10,则b c
的值为( )a+b b+c
A.
11 21
B.
21 11
C.
110 21
D.
210 11
答
∵
=20,a b
=10,b c
∴得
=a+b b+c
=
+1a b 1+
c b
=20+1 1+
1 10
.210 11
故选D.