\[\frac{x^{2} - x - 12}{x^{2} + x - 2} \geq 0\]
\[x^{2} - x - 12 =\]
\[= x^{2} - 4x + 3x - 12 =\]
\[= x(x - 4) + 3(x - 4) =\]
\[= (x - 4)(x + 3)\]
\[x^{2} + x - 2 = x^{2} + 2x - x - 2 =\]
\[= x(x + 2) - (x + 2) =\]
\[= (x + 2)(x - 1)\]
\[\frac{(x + 3)(x - 4)}{(x + 2)(x - 1)} \geq 0\]