题目内容
化简
(1)
lg25+lg2-lg
-log29×log32;
(2)
•b-2(
•b)-1÷(4-1a
b-3)
×
.
(1)
| 1 |
| 2 |
| 0.1 |
(2)
| 5 |
| 6 |
| 3 | a |
| a |
| 2 |
| 3 |
| 1 |
| 2 |
| ab |
分析:(1)利用对数的运算性质,把
lg25+lg2-lg
-log29×log32等价转化为lg5+lg2+
-2,由此能求出结果.
(2)利用有理数指数幂的性质,把
•b-2(
•b)-1÷(4-1a
b-3)
×
等价转化为
×4×a
-
-
+
×b-2-1+
+
,由此能求出结果.
| 1 |
| 2 |
| 0.1 |
| 1 |
| 2 |
(2)利用有理数指数幂的性质,把
| 5 |
| 6 |
| 3 | a |
| a |
| 2 |
| 3 |
| 1 |
| 2 |
| ab |
| 5 |
| 6 |
| 1 |
| 3 |
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 2 |
| 3 |
| 2 |
| 1 |
| 2 |
解答:解:(1)
lg25+lg2-lg
-log29×log32
=lg5+lg2+
-2
=-
.
(2)
•b-2(
•b)-1÷(4-1a
b-3)
×
=
×4×a
-
-
+
×b-2-1+
+
=
.
| 1 |
| 2 |
| 0.1 |
=lg5+lg2+
| 1 |
| 2 |
=-
| 1 |
| 2 |
(2)
| 5 |
| 6 |
| 3 | a |
| a |
| 2 |
| 3 |
| 1 |
| 2 |
| ab |
=
| 5 |
| 6 |
| 1 |
| 3 |
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 2 |
| 3 |
| 2 |
| 1 |
| 2 |
=
| 10 |
| 3b |
点评:本题考查对数的运算性质和有理数指数幂的性质的运用,是基础题,解题时要认真审题,仔细解答.
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