Question

$(x - 1)(x - 2) = 6$

Answer 1

$(x - 1)(x - 2) = 6 \\ {x}^{2} - 2x - x + 2 = 6 \\ {x}^{2} - 3x - 4= 0 \\ \\ delta = 9 + 16 = 25 \\ \\ x = \frac{3 + \sqrt{25} }{2} = \frac{3 + 5}{2} = \frac{8}{2} = 4 \\ \\ x = \frac{3 - \sqrt{25} }{2} = \frac{3 - 5}{2} = \frac{ - 2}{2} = - 1$