\[x^{2} + px - 6 = 0;\ \ \ x_{1} = 2\]
\[2^{2} + 2p - 6 = 0\]
\[4 + 2p - 6 = 0\]
\[2p = 2\]
\[p = 1.\]
\[x^{2} + x - 6 = 0\]
\[x_{1} + x_{2} = - 1\]
\[2 + x_{2} = - 1\]
\[x_{2} = - 3.\]
\[Ответ:\ \ x_{2} = - 3,\ \ \ p = 1.\]