For solving equations by completing the square, how do you solve x2 - 4x + 12 = 0?

X² - 4x + 12 = 0
x = -(-4) /- √((-4)² - 4(1)(12))
                     2(1)
x = 4 +/- √(16 - 48)
                 2
x = 4 +/- √(-32)
              2
x = 4 +/- 4i√(2)
             2
x = 2 + 2i√(2)
x = 2 + 2i√(2)      x = 2 - 2i√(2)

The solution the problem is {2 + 2i√(2), 2 - 2i√(2)}.