第70页 - 同步练习八年级数学苏科版江苏凤凰科学技术出版社

$ ±\frac {11}{5}$

±9

$ ±\sqrt {13}$

2

4

$ -\sqrt {2}$

$\frac {1}{\sqrt {2}}$

$\sqrt[{3}] {6}$

2或-4

9或81

A

B

解: x-1=±5

x=6或-4

解: -(x-3)=3

x=0

$解:∵(\sqrt {7})^{2}+(\sqrt {6})^{2}=13$

$\sqrt {7}×\sqrt {6}=\sqrt {42}$

$∴原式=\sqrt {(\sqrt {7})^{2}-2×\sqrt {42}+(\sqrt {6})^{2}}=\sqrt {(\sqrt {7}-\sqrt {6})^{2}}=\sqrt {7}-\sqrt {6}$