第45页

信息发布者:
被开方数
每个二次根式
同类二次根式
​$ C$​
$\sqrt{2}$
解:​$7\sqrt {5}-3\sqrt {5}$​
​$=(7-3)\sqrt {5}$​
​$=4\sqrt {5}$​
解:​$3\sqrt {2}-\sqrt {8}$​
​$=3\sqrt {2}-2\sqrt {2}$​
​$=(3-2)\sqrt {2}$​
​$=\sqrt {2}$​
解:​$\sqrt {18}+\sqrt {50}$​
​$=3\sqrt {2}+5\sqrt {2}$​
​$=(3+5)\sqrt {2}$​
​$=8\sqrt {2}$​
解:​$-2\sqrt {75}+3\sqrt {12}$​
​$=-2×5\sqrt {3}+3×2\sqrt {3}$​
​$=-10\sqrt {3}+6\sqrt {3}$​
​$=(-10+6)\sqrt {3}$​
​$=-4\sqrt {3}$​
解:​$\sqrt {27}-6\sqrt {\frac {1}{3}}$​
​$=3\sqrt {3}-6×\frac {\sqrt {3}}{3}$​
​$=3\sqrt {3}-2\sqrt {3}$​
​$=(3-2)\sqrt {3}$​
​$=\sqrt {3}$​
解:​$\sqrt {8ab}-b\sqrt {\frac {a}{2b}}$​
​$=2\sqrt {2ab}-b×\frac {\sqrt {2ab}}{2b}$​
​$=2\sqrt {2ab}-\frac {1}{2}\sqrt {2ab}$​
​$=(2-\frac {1}{2})\sqrt {2ab}$​
​$=\frac {3}{2}\sqrt {2ab}$​
解:​$\sqrt {75}+\sqrt {27}-\sqrt {48}$​
​$=5\sqrt {3}+3\sqrt {3}-4\sqrt {3}$​
​$=(5+3-4)\sqrt {3}$​
​$=4\sqrt {3}$​
解:​$\sqrt {3}-\sqrt {12}+\sqrt {\frac {1}{3}}$​
​$=\sqrt {3}-2\sqrt {3}+\frac {\sqrt {3}}{3}$​
​$=(1-2+\frac {1}{3})\sqrt {3}$​
​$=-\frac {2\sqrt {3}}{3}$​