题目内容

(1)求值:lg52+
2
3
lg8+lg5•lg20+(lg2)2

(2)求值:(0.0081)-
1
4
-[3×(
7
8
)
0
]-1×[81-0.25+(3
3
8
)
-
1
3
]-
1
2
-10×0.027
1
3
(1)lg52+
2
3
lg8+lg5•lg20+(lg2)2

=2lg5+
2
3
lg23+lg5(1+lg2)+(lg2)2

=2lg5+2lg2+lg5(1+lg2)+(lg2)2
=2(lg5+lg2)+lg5+lg5•lg2+(lg2)2
=2+lg5+lg2(lg5+lg2)=3.
(2)(0.0081)-
1
4
-[3×(
7
8
)0]-1×
[81-0.25+(3
3
8
)-
1
3
]-
1
2
-10×0.027
1
3

=((0.3)4)-
1
4
-3-1×[(34)-
1
4
+(
3
2
)-1]-
1
2
-10×((0.3)3)
1
3

=
10
3
-
1
3
(
1
3
+
2
3
)-
1
2
-10•0.3

=
10
3
-
1
3
-3

=0.
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