\[x^{2} + 5x - 6 < 0\]
\[x_{1} + x_{2} = - 5;\ \ x_{1} \cdot x_{2} = - 6\]
\[x_{1} = - 6;\ \ x_{2} = 1\]
\[(x + 6)(x - 1) < 0\]
\[x \in ( - 6;1).\]