\[\boxed{\mathbf{548\ (548).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ \sqrt{3a^{2}} = a\sqrt{3};\ \ a \geq 0\ \]
\[2)\ \sqrt{5b^{2}} = |b|\sqrt{5} = - b\sqrt{5},\]
\[b \leq 0;\]
\[3)\ \sqrt{12a^{4}} = 2a²\sqrt{3};\ \]
\[4)\ \sqrt{c^{5}} = \sqrt{c^{4} \cdot c} = c²\sqrt{c}.\]