问题 解答题
(1)化简与求值:(0.0081)-
1
4
-[3(
7
8
)
0
]-1•[81-0.25+(
27
8
)
-
1
3
]-
1
2
-10×0.027
1
3

(2)化简与求值:log2
7
48
+log212-
1
2
log242-1
答案

(1)(0.0081)-

1
4
-[3(
7
8
)
0
]-1•[81-0.25+(
27
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×(0.33)
1
3

=

10
3
-
1
3
×(
1
3
+
2
3
)-
1
2
-3

=

10
3
-
1
3
-3=0;

(2)log2

7
48
+log212-
1
2
log242-1

=

1
2
log2
7
48
+log212-
1
2
log242-1

=

1
2
(log2
7
48
-log242)+log212-1

=

1
2
log2
1
288
+log212-1

=-

1
2
log22×122+log212-1

=-

1
2
(1+2log212)+log212-1

=-

1
2
-1=-
3
2

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