\[\boxed{\mathbf{740\ (740).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ x² + bx + 6 = 0\]
\[x_{1} \cdot x_{2} = 6\]
\[x_{1} + x_{2} = - b\]
\[x_{1} = 6,\ \ x_{2} = 1,\ \ - b = 7,\ \ \]
\[b = - 7\]
\[x_{1} = - 6,\ \ x_{2} = - 1,\ \ \]
\[- b = - 7,\ \ b = 7\]
\[x_{1} = 3,\ \ x_{2} = 2,\ \ - b = 5,\]
\[\ b = - 5\]
\[x_{1} = - 3,\ \ x_{2} = - 2,\ \ \]
\[- b = - 5,\ \ b = 5\]
\[Ответ:\ при\ b = - 7;7;\ b = - 5;5.\]
\[2)\ x² + bx - 12 = 0\]
\[x_{1} \cdot x_{2} = - 12\]
\[x_{1} + x_{2} = - b\]
\[x_{1} = - 12,\ \ x_{2} = 1,\]
\[b = 11\]
\[x_{1} = - 1,\ \ x_{2} = 12,\]
\[b = - 11\]
\[x_{1} = 6,\ \ x_{2} = - 2,\ \ b = - 4\]
\[x_{1} = - 6,\ \ x_{2} = 2,\ \ b = 4\]
\[x_{1} = - 4,\ \ x_{2} = 3,\ \ b = 1\]
\[x_{1} = - 3,\ \ x_{2} = 4,\ \ b = - 1\]
\[Ответ:при\ b = 11;\ - 11;\ \]
\[b = - 4;4;b = 1;\ - 1.\]