问题 解答题
计算求值
(I)0.064
1
3
-(-
7
8
)0+160.75+0.25
1
2

(Ⅱ)lg25+lg5-lg4+lg22.
答案

(I)0.064

1
3
-(-
7
8
)0+160.75+0.25
1
2

=(0.43)

1
3
-1+(24)
3
4
+(0.52)
1
2

=0.4-1+8+0.5=

79
10

(Ⅱ)lg25+lg5-lg4+lg22

=lg25+lg5-2lg2+lg22

=(lg5+lg2)2-2lg5lg2-2lg2+lg5

=1-2lg2(lg5+1)+lg5.

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