问题 解答题
(1)计算:(
32
)6
-
7
5
×(
25
49
)
1
2
-(-2013)0

(2)已知log73=a,log74=b,用a,b表示log4948.
答案

(1)(

32
)6-
7
5
×(
25
49
)
1
2
-(-2013)0

=2

6
3
-
7
5
×
5
7
-1

=2-1-1

=0.

(2)∵log73=a,log74=b,

∴log4948=

1
2
log7(3×16)

=

1
2
(log73+log716)

=

1
2
(log73+2log74)

=

1
2
(a+2b).

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