using the quadratic formula, you can solve this quite easily.,,,,
a b c
x² - 12x + 59 = 0 a(1)...b(-12).....c(59)
(-b +/- √b² - 4ac) / (2a) (substitute the values for a, b, and c)
(-(-12) +/- √ (-12)² - 4 (1) (59)) / 2(1)
(12 +/- √-92) / 2 ( √-92 can be written as √-1√4√23)
(12 +/- √-1√4√23) / 2 (√-1 = i and √4 = 2)
6 +/- 23i