第119页 - 江苏版启东中学作业本八年级数学（上下册）

B

C

A

6

$3\sqrt{2}$

$2\sqrt{6}$

$15\sqrt{5}$

$ \begin{aligned} 解：原式&= \sqrt{10^2×3} \\ &=10\sqrt3 \\ \end{aligned}$

$ $

$ \begin{aligned}解：原式&= \sqrt{0.01}× \sqrt{0.16} \\ &=0.1×0.4 \\ &=0.04 \\ \end{aligned}$

$ \begin{aligned} 解：原式&=\sqrt{9×8a^2·a^2·b^2}·b \\ &=\sqrt 9·\sqrt {a^2}·\sqrt {b^2}·b·\sqrt{8a^2} \\ &=6a^2b \sqrt{2b} \\ \end{aligned}$

$ \begin{aligned} 解：原式&=\sqrt{7^2×7(x^2)^2y^2·y} \\ &=7x^2y \sqrt{7y} \\ \end{aligned}$

$ \begin{aligned}解：原式&= \sqrt{(51+49)×(51-49)} \\ &=10\sqrt{2} \\ \end{aligned}$

$ \begin{aligned} 解：原式&=\sqrt{a^2·b^2·a} \\ &=\sqrt{a^2}·\sqrt{b^2}·\sqrt a \\ &=a·(-b)·\sqrt a \\ &=-ab \sqrt a \\ \end{aligned}$

$ \begin{aligned}解：原式&= \sqrt{8×\frac{1}{2}} \\ &=2 \\ \end{aligned}$

$ \begin{aligned}解：原式&= \sqrt{6×10×15} \\ &= \sqrt{900} \\ &=30 \\ \end{aligned}$

$ \begin{aligned}解：原式&= \sqrt{\frac{1}{2}×\frac{9}{4}×8} \\ &=3 \\ \end{aligned}$

$ \begin{aligned} 解：原式&= \sqrt{\frac{1}{ab}×a^3b} \\ &= \sqrt{a^2} \\ &=|a| \\ \end{aligned}$