\[\boxed{\text{110.\ }\text{ОК\ ГДЗ\ -\ домашка\ на\ 5}}\]
\[\textbf{а)}\ x^{2} + 2x - 15 = 0\]
\[D_{1} = 1 + 15 = 16\]
\[x_{1} = - 1 + 4 = 3;\ \ \]
\[x_{2} = - 1 - 4 = - 5.\]
\[Ответ:\ \ x = - 5;\ \ x = 3.\]
\[\textbf{б)}\ 2x^{2} - x - 3 = 0\]
\[D = 1 + 24 = 25\]
\[x_{1} = \frac{1 + 5}{4} = 1,5;\ \ \]
\[\ x_{2} = \frac{1 - 5}{4} = - 1.\]
\[Ответ:x = - 1;\ \ x = 1,5.\]
\[\textbf{в)}\ 3x^{2} - 22x + 7 = 0\]
\[D_{1} = 121 - 21 = 100\]
\[x_{1} = \frac{11 + 10}{3} = 7;\ \ \]
\[\ x_{2} = \frac{11 - 10}{3} = \frac{1}{3}.\]
\[Ответ:x = \frac{1}{3};\ \ x = 7.\]
\[\textbf{г)}\ 3x^{2} + 6x + 10 = 0\]
\[D_{1} = 9 - 30 = - 21 < 0\]
\[нет\ корней.\]
\[Ответ:нет\ корней.\]