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
=y,则x+2y的值为( )8 3
A. 3
B. 8
C. 4
D. log48
答
∵2x=3,∴x=log23=log49.
∴x+2y=log49+2log4
=log4(9×8 3
)=log464=3.64 9
故选A.