[tex]x ^{2} - 11x + 10 = 0 \\ d = b ^{2} - 4ac \\ d = - 11 {}^{2} - 4 \times 1 \times 10 = 121 - 40 = 81 \\ x1 = \frac{11 + \sqrt{81} }{2} = 10 \\ x2 = \frac{11 - \sqrt{81} }{2} = 1[/tex]