\[\boxed{\text{1174\ (1174).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[+ \text{ac} - a^{2} - \text{bc} + \text{ab} = 0\ \]
\[\boxed{\text{1174.\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[ax + by = c\]
\[( - 2;1):\ \]
\[2a + b = c\ \]
\[2 \cdot ( - 2) + 1 = - 4 + 1 = - 3,\ \ \ \]
\[тогда\]
\[2x + y = - 3.\]