\[\boxed{\mathbf{778.}\mathbf{ОК\ ГДЗ - домашка\ на}\ 5}\]
\[\mathbf{Построим\ вектроры\ }\overrightarrow{a},\ \overrightarrow{b}\ и\ \overrightarrow{c}.\]
\[\textbf{а)}\ 2\overrightarrow{a} + 3\overrightarrow{b} - 4\overrightarrow{c};\]
\[\textbf{б)}\frac{1}{2}\overrightarrow{a} - \overrightarrow{b} + \frac{1}{3}\overrightarrow{c}\text{\ .}\]