问题
解答题
计算: (1)已知x>0,化简(2x
(2)log2.56.25+lg
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答案
(1)(2x
+31 4
)(2x3 2
-31 4
)-4x-3 2
(x-x1 2
) 1 2
=(2x
)2-(31 4
)2-4x-3 2
•x+4x-1 2
•x1 2
…(3分)1 2
=4x
-33-4x1 2
+4…(5分) 1 2
=-23.…(6分)
(2)log2.56.25+lg
+ln1 100
+21+log23=log2.52.52+lg10-2+lnee
+2×2log23…(9分)1 2
=2-2+
+2×3 …(12分)1 2
=6
.…(13分)1 2