问题 解答题
计算:(1)(27
69
70
)0-[1-(
1
2
)
-2
]÷(3
3
8
)
1
3

(2)(
325
-
125
425

(3)
lg2+lg5-lg8
lg50-lg40

(4)log2
1
25
×log3
1
8
×log5
1
9
答案

(1)原式=1-(1-4)÷

3
2

=1-(-2)=3.

(2)原式=(5

2
3
-5
3
2
÷5
1
2

=5

1
6
-5.

(3)原式=

lg
2×5
8
lg
50
40

lg
5
4
lg
5
4
=1.

(4)原式=

lg
1
25
lg2
×
lg
1
8
lg3
×
lg
1
9
lg5

=

-2lg5
lg2
×
-3lg2
lg3
×
-2lg3
lg5

=-12.

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