题目内容
计算下列各式的值,写出计算过程
(1)4x
(-3x
y-
)÷(-6x-
y-
);
(2)(lg5)2+lg50•lg2.
(1)4x
| 1 |
| 4 |
| 1 |
| 4 |
| 1 |
| 3 |
| 1 |
| 2 |
| 2 |
| 3 |
(2)(lg5)2+lg50•lg2.
考点:对数的运算性质
专题:函数的性质及应用
分析:利用指数和对数的运算法则和运算性质求解.
解答:
解:(1)4x
(-3x
y-
)÷(-6x-
y-
)
=4×(-3)÷(-6)x
+
-(-
)y -
-(-
)
=2xy
.
(2)(lg5)2+lg50•lg2
=(lg5)2+lg(10×5)lg
=(lg5)2+(1+lg5)(1-lg5)
=(lg5)2+1-(lg5)2
=1.
| 1 |
| 4 |
| 1 |
| 4 |
| 1 |
| 3 |
| 1 |
| 2 |
| 2 |
| 3 |
=4×(-3)÷(-6)x
| 1 |
| 4 |
| 1 |
| 4 |
| 1 |
| 2 |
| 1 |
| 3 |
| 2 |
| 3 |
=2xy
| 1 |
| 3 |
(2)(lg5)2+lg50•lg2
=(lg5)2+lg(10×5)lg
| 10 |
| 5 |
=(lg5)2+(1+lg5)(1-lg5)
=(lg5)2+1-(lg5)2
=1.
点评:本题考查指数式和对数式的运算,解题时要认真审题,是基础题.
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