\[1)\ (x + 2yi) + (3y - 2xi) = 2 + 4i\]
\[(x + 3y) + (2y - 2x)i = 2 + 4i\]
\[Действительная\ часть:\]
\[x + 3y = 2\]
\[x = 2 - 3y.\]
\[Мнимая\ часть:\]
\[2y - 2x = 4\]
\[y - x = 2\]
\[y - 2 + 3y = 2\]
\[4y = 4\]
\[y = 1;\]
\[x = 2 - 3 = - 1.\]
\[Ответ:\ \ x = - 1;\ y = 1.\]
\[2)\ (2x + 5yi) + (y + xi) = 2 + i\]
\[(2x + y) + (5y + x)i = 2 + i\]
\[Действительная\ часть:\]
\[2x + y = 2\]
\[y = 2 - 2x.\]
\[Мнимая\ часть:\]
\[5y + x = 1\]
\[5(2 - 2x) + x = 1\]
\[10 - 10x + x = 1\]
\[9x = 9\]
\[x = 1;\]
\[y = 2 - 2 = 0.\]
\[Ответ:\ \ x = 1;\ y = 0.\]
\[3)\ y - \frac{10}{x} + 7i = \frac{8i}{x} + yi - 2\]
\[\left( y - \frac{10}{x} \right) + 7i = - 2 + \left( y + \frac{8}{x} \right)i\]
\[Действительная\ часть:\]
\[y - \frac{10}{x} = - 2\]
\[y = \frac{10}{x} - 2.\]
\[Мнимая\ часть:\]
\[7 = y + \frac{8}{x}\]
\[\frac{10}{x} - 2 + \frac{8}{x} = 7\]
\[\frac{18}{x} = 9\]
\[x = 2;\]
\[y = 5 - 2 = 3.\]
\[Ответ:\ \ x = 2;\ y = 3.\]
\[4)\ \frac{1}{x} + \frac{1}{y} + \frac{i}{x} = \frac{3}{x} - \frac{i}{y} + 3i\]
\[\left( \frac{1}{x} + \frac{1}{y} \right) + \frac{1}{x} \bullet i = \frac{3}{x} + \left( 3 - \frac{1}{y} \right)i\]
\[Действительная\ часть:\]
\[\frac{1}{x} + \frac{1}{y} = \frac{3}{x}\]
\[\frac{1}{y} = \frac{2}{x}\]
\[y = \frac{1}{2}x.\]
\[Мнимая\ часть:\]
\[\frac{1}{x} = 3 - \frac{1}{y}\]
\[\frac{1}{x} = 3 - \frac{2}{x}\]
\[\frac{3}{x} = 3\]
\[x = 1;\text{\ \ \ }\]
\[y = \frac{1}{2}.\]
\[Ответ:\ \ x = 1;\ y = \frac{1}{2}.\]