[tex] {3x}^{2} - x - 2 = {3x}^{2} - 3x + 2x - 2 = 3x( \frac{ {3x}^{2} }{3x} - \frac{3x}{3x}) + 2( \frac{2x}{2} - \frac{2}{2}) = 3x( {x}^{2 - 1} - 1) + 2(x - 1) = 3x(x - 1) + 2(x - 1) = (x - 1)( \frac{3x(x - 1)}{x - 1} + \frac{2x(x - 1)}{x - 1}) = (x - 1)(3x + 2) [/tex]
