X^2-12x+16=0
- b +/- sqrt( b^2 - 4ac)
x = ---------------------------
2a
-(-12)+/-sqrt(12^2 - 4*16
x = --------------------------------
2
12 +/- sqrt(144 - 56)
x = --------------------------------
2
12+/- sqrt88 12+/.- sqrt(4*22)
x = ---------------- = --------------------
2 2
x = (12 +/-2sqrt22}/2
x = 6 +sqrt22 and x = 6 - sqrt22