已知2x=3,log483=y,则x+2y的值为(  ) A.3 B.8 C.4 D.log48

问题描述:

已知2x=3,log4

8
3
=y,则x+2y的值为(  )
A. 3
B. 8
C. 4
D. log48

∵2x=3,∴x=log23=log49.
∴x+2y=log49+2log4

8
3
=log4(9×
64
9
)
=log464=3.
故选A.