$π,−\sqrt[{3}]{-20}, \sqrt{\frac{1}{3}},0.7171171117...(每相邻两个7之间依次多1个1)$
$0,0.54, \sqrt{(−5)²},−\frac{13}{7}$
$解:(1)(2x-1)²=9$ $2x-1=±3$ $x_{1}=2或x_{2}=−1$
$解:(2)(3x-1)³=\frac{125}{64}$ $3x-1=\frac{5}{4}$ $3x=\frac{9}{4}$ $x=\frac{3}{4}$
$解:(1)原式=4×\frac{3}{2}-(-8)×\frac{1}{4}$ $=6-(-2)$ $=6+2$ $=8$ $解:(2)原式=5+(-2)-\frac{2}{3}+\frac{2}{3}-1$ $=5-2-1$ $=2$
$解:(2)∵数轴上点A,B分别表示数−1和- \sqrt{5},$ $∴点A与点B之间的距离a=|-1−(-\sqrt{5})|=\sqrt{5}−1.$ $由(1)，知b=4-\sqrt{5},$ $∴a−b=(\sqrt{5}-1)−(4−\sqrt{5})=\sqrt{5}−1−4+\sqrt{5}=−5+2\sqrt{5}$ $∴a−b的值为−5+2\sqrt{5}$
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