Решить квадратное уравнение

1)
${x}^{2} - x = 2 \\ {x}^{2} - x - 2 = 0 \\ d = {b}^{2} - 4ac = 1 - 4 \times ( - 2) = 1 + 8 = 9 = {3}^{2} \\ x1 = \frac{ - b + \sqrt{d} }{2a} = \frac{1 + 3}{2} = \frac{4}{2} = 2 \\ x2 = \frac{ - b - \sqrt{d} }{2a} = \frac{1 - 3}{2} = \frac{ - 2}{2} = - 1$
Ответ: -1; 2.

2)
${x}^{2} - 4x = 5 \\ {x}^{2} - 4x - 5 = 0 \\ d = {b}^{2} - 4ac = 16 - 4 \times ( - 5) = 16 + 20 = 36 = {6}^{2} \\ x1 = \frac{4 + 6}{2} = \frac{10}{2} = 5 \\ x2 = \frac{4 - 6}{2} = \frac{ - 2}{2} = - 1$
Ответ: -1; 5.

3)
${x}^{2} + 8x = - 12 \\ {x}^{2} + 8x + 12 = 0 \\ d = {b}^{2} - 4ac = 64 - 4 \times 12 = 64 - 48 = 16 \\ x1 = \frac{ - 8 + 4}{2} = \frac{ - 4}{2} = - 2 \\ x2 = \frac{ - 8 - 4}{2} = \frac{ - 12}{2} = - 6$
Ответ: -6; -2.