问题
解答题
计算下列各式值 (1)(2x)
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答案
(1)(2x)
(-3x1 4
y-1 4
)÷[(-27)1 3
x-2 3
y-1 2
]2 3
=-(2
×31-3×1 4
)•x2 3
+1 4
+1 4
•y-1 2
+1 3 2 3
=-
x4 2 3
.3 y
(2)log2
+log212-7 48
log242=1 2 1 2
-log 72 1 2
+log (24×3)2
-log (22×3)2 1 2 log (2×3×7)2
=1 2
-log 72 1 2
-log 242 1 2
+log 32
+log 222
-log 32 1 2
-log 22 1 2
-log 32 1 2 log 72
=-
×4+2-1 2 1 2
=-
.1 2