\[\boxed{\mathbf{916.ОК\ ГДЗ - домашка\ на}\ 5}\]
\[Дано:\]
\[\overrightarrow{a}\ и\ \overrightarrow{b} - не\ коллинеарны.\ \]
\[Найти:\]
\[x;y.\]
\[\textbf{а)}\ 3\overrightarrow{a} - x\overrightarrow{b} = y\overrightarrow{a} + \overrightarrow{b}\]
\[y = 3;\ x = - 1.\]
\[\textbf{б)}\ 4\overrightarrow{a} - x\overrightarrow{a} + y\overrightarrow{b} + 5\overrightarrow{b}\]
\[y = - 5;\ x = 4.\]
\[\textbf{в)}\ x\overrightarrow{a} + 3\overrightarrow{b} - y\overrightarrow{b} = 0\]
\[x = 0;\ \ y = 3.\]
\[\textbf{г)}\ \overrightarrow{a} + \overrightarrow{b} - 3y\overrightarrow{a} + x\overrightarrow{b} = 0\]
\[y = \frac{1}{3};\ x = - 1.\]