\[x_{1} + x_{2} = - 5;\ \ x_{1} \cdot x_{2} = - 24\]
\[x_{1} = - 8;\ \ x_{2} = 3\]
\[x^{2} + 5x - 24 = (x + 8)(x - 3).\]
\[x^{2} - 4x + 3 = 0\]
\[x_{1} + x_{2} = 4;\ \ x_{1} \cdot x_{2} = 3\]
\[x_{1} = 3;\ \ x_{2} = 1\]
\[- x^{2} + 4x - 3 =\]
\[= - (x - 3)(x - 1) =\]
\[= (x - 3)(1 - x).\]