\[\boxed{\mathbf{548\ (548).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ \sqrt{3a^{2}} = a\sqrt{3};\ \ a \geq 0\ \]
\[2)\ \sqrt{5b^{2}} = |b|\sqrt{5} = - b\sqrt{5},\]
\[b \leq 0;\]
\[3)\ \sqrt{12a^{4}} = 2a²\sqrt{3};\ \]
\[4)\ \sqrt{c^{5}} = \sqrt{c^{4} \cdot c} = c²\sqrt{c}.\]
\[\boxed{\mathbf{5}\mathbf{4}\mathbf{8}\mathbf{\text{.\ }}Еуроки\ - \ ДЗ\ без\ мороки}\]
\[a - четное,\ \ b - нечетное\]
\[b = 2a + 1\]
\[1)\ (a + b)b =\]
\[= (a + 2a + 1)(2a + 1) =\]
\[2)\frac{\text{ab}}{2} = \frac{a(2a + 1)}{2} =\]