第130页 - 经纶学典新课时作业八年级数学上下册【江苏国标】

分解因式

$ \sqrt{b}$

≥0

B

$10\sqrt{3}$

$-6\sqrt{3}$

$(1-a) \sqrt{1-a}$

$ \begin{aligned}解:原式&=3(a-1) \\ &=3a-3 \\ \end{aligned}$

$解:∵x＞y＞0$

$ \begin{aligned}∴原式&=\sqrt{(\sqrt{2}x-\sqrt{2}y)^2} \\ &=\sqrt{2}x-\sqrt{2}y \\ \end{aligned}$

$ \begin{aligned}解:原式&=3×5×2\sqrt{5} \\ &=30\sqrt{5} \\ \end{aligned}$

$ \begin{aligned}解:原式&=3\sqrt{24a^3×\frac {a}{2}} \\ &=3\sqrt{12a^4} \\ &=6\sqrt{3}a² \\ \end{aligned}$

B

C

D

$解:∵x≥0，25+y≥0$

$ \begin{aligned}∴原式&=\sqrt{x^2(25+y)} \\ &=x\sqrt{25+y} \\ \end{aligned}$

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