问题
解答题
将下列对数式化为指数式求x值: (1)logx27=
(2)log2x=-
(3)log5(log2x)=0; (4)x=log27
(5)x=log
|
答案
(1)∵logx27=
,∴x3 2
=27,∴x=273 2
=32=9;2 3
(2)log2x=-
,∴x=2-2 3
=2 3
=1 3 22
;3 2 2
(3)∵log5(log2x)=0,∴log2x=1,∴x=2;
(4)∵x=log27
,∴27x=1 9
,化为33x=3-2,∴3x=-2,得到x=-1 9
;2 3
(5)∵x=log
16,∴(1 2
)x=16,∴2-x=24,解得x=-4.1 2