[tex] {x}^{2} - 12x + 59 = 0 \\ {x}^{2} - 12x + 36 + 23 = 0 \\ {x}^{2} - 12x + 36 = - 23 \\ {(x - 6)}^{2} = - 23 \\ x - 6 = + - \sqrt{ - 23} = + - i \sqrt{23} \\ x = 6 + - i \sqrt{23} [/tex]
mean
[tex]x = 6 + i \sqrt{23} [/tex]
or
[tex] x = 6 - i \sqrt{23} [/tex]