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信息发布者:
C
$\sqrt{3}$
$3\sqrt{3}$
解:原式​$=2\sqrt {3}+3\sqrt {3}$​
​$=5\sqrt {3}$​
解:原式​$=\sqrt {2}-4\sqrt {2}$​
​$=-3\sqrt {2}$​
$ \begin{aligned}解:原式&=\sqrt {3x}-3\sqrt {3x} \\ &=-2 \sqrt{3x} \\ \end{aligned}$
解:原式​$=3\sqrt {3}+2\sqrt {3}-4\sqrt {3}$​
​$= \sqrt {3}$​
解:原式​$=\sqrt {3}-1-2\sqrt {3}$​
​$=-1-\sqrt {3}$​
解:原式​$=2\sqrt {6}+\frac {\sqrt {2}}{2}-\frac {\sqrt {2}}{4}+\sqrt {6}$​
​$=3\sqrt {6}+\frac {\sqrt {2}}{4}$​

$解:(1)此矩形的周长为(\frac{1}{2}\sqrt{32}+\frac{1}{3}\sqrt{18})×2=(2\sqrt{2}+\sqrt 2)×2=6\sqrt{2}.$
$ \begin{aligned}(2)此矩形的面积&=\frac{1}{2}\sqrt{32}× \frac{1}{3}\sqrt{18} \\ &=2\sqrt{2}× \sqrt{2} \\ &=4. \\ \end{aligned}$
$故与此矩形面积相等的正方形的对角线的长为\sqrt {2^2+2^2} =2\sqrt{2}.$
C
$-\sqrt{5}$
$2$