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求下列各式的值:(1)log26-log23;(2)lg5+lg2;(3)log53+log513;(4)log35-log315.

题目详情
求下列各式的值:
(1)log26-log23;
(2)lg5+lg2;
(3)log53+log5
1
3

(4)log35-log315.
求下列各式的值:
(1)log26-log23;
(2)lg5+lg2;
(3)log53+log5
1
3

(4)log35-log315.

22

55
1
3

(4)log35-log315.
1
3
131133
33
▼优质解答
答案和解析
(1)log226-log223=log222+log223-log223=1;
(2)lg5+lg2=lg10=1;
(3)log553+log55
1
3
=log5(3×
1
3
)=0;
(4)log35-log315=log35-log33-log35=-1.
1
3
13111333=log55(3×
1
3
)=0;
(4)log35-log315=log35-log33-log35=-1.
1
3
13111333)=0;
(4)log335-log3315=log335-log333-log335=-1.