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一、选择题
1. 化简$\sqrt{\dfrac{1}{5}+\dfrac{1}{6}}$的结果为 （
A.$\dfrac{\sqrt{11}}{30}$
B.$30\sqrt{330}$
C.$\dfrac{\sqrt{330}}{30}$
D.$30\sqrt{11}$
1. 化简$\sqrt{\dfrac{1}{5}+\dfrac{1}{6}}$的结果为 （
C
）A.$\dfrac{\sqrt{11}}{30}$
B.$30\sqrt{330}$
C.$\dfrac{\sqrt{330}}{30}$
D.$30\sqrt{11}$
答案
1.C
2. 下列运算正确的是 （
A.$\sqrt[3]{-27}=3$
B.$(π - 3.14)^0 = 1$
C.$(\frac{1}{2})^{-1} = -2$
D.$\sqrt{9} = \pm 3$
B
）A.$\sqrt[3]{-27}=3$
B.$(π - 3.14)^0 = 1$
C.$(\frac{1}{2})^{-1} = -2$
D.$\sqrt{9} = \pm 3$
答案
2.B
3.化简$\sqrt{8}$的结果是（
A.2
B.$2\sqrt{2}$
C.$-2\sqrt{2}$
D.$\pm\sqrt{2}$
B
）A.2
B.$2\sqrt{2}$
C.$-2\sqrt{2}$
D.$\pm\sqrt{2}$
答案
3.B
4. 下列二次根式是最简二次根式的是（
A.$\sqrt{8}$
B.$\sqrt{\dfrac{1}{2}}$
C.$\sqrt{10}$
D.$\dfrac{3}{\sqrt{5}}$
C
）A.$\sqrt{8}$
B.$\sqrt{\dfrac{1}{2}}$
C.$\sqrt{10}$
D.$\dfrac{3}{\sqrt{5}}$
答案
4.C
5. 下列运算错误的是 （
A.$\sqrt{14} × \sqrt{7} = 7\sqrt{2}$
B.$\sqrt{60} ÷ \sqrt{5} = 2\sqrt{3}$
C.$\sqrt{(-4)^2} = 4$
D.$3\sqrt{2} - \sqrt{2} = 3$
D
）A.$\sqrt{14} × \sqrt{7} = 7\sqrt{2}$
B.$\sqrt{60} ÷ \sqrt{5} = 2\sqrt{3}$
C.$\sqrt{(-4)^2} = 4$
D.$3\sqrt{2} - \sqrt{2} = 3$
答案
5.D
6. 下列计算正确的是（
A.$3\sqrt{3} - 4\sqrt{2} = 12\sqrt{2}$
B.$\sqrt{(-9) × (-4)} = \sqrt{-9} × \sqrt{-4} = 6$
C.$-3\sqrt{\frac{2}{3}} = \sqrt{(-3)^2 × \frac{2}{3}} = \sqrt{6}$
D.$\sqrt{13^2 - 12^2} = \sqrt{(13+12)(13-12)} = 5$
D
）A.$3\sqrt{3} - 4\sqrt{2} = 12\sqrt{2}$
B.$\sqrt{(-9) × (-4)} = \sqrt{-9} × \sqrt{-4} = 6$
C.$-3\sqrt{\frac{2}{3}} = \sqrt{(-3)^2 × \frac{2}{3}} = \sqrt{6}$
D.$\sqrt{13^2 - 12^2} = \sqrt{(13+12)(13-12)} = 5$
答案
6.D
