Question 386047
when you complete the square , you are squaring some binomial of the form (x + ?)


so squaring (x + ?) gives ___ x^ + 2?x + ?^2


in this case , 2?x = -4x
dividing by 2x ___ ? = -2


(x - 2)^2 = x^2 - 4x + 4
so you add 4 to the original equation ___ x^2 - 4x + 4 = 12 ___ (x - 2)^2 = 12


taking square root ___ x - 2 = ± sqrt(12)


adding 2 , and simplifying ___ x = 2 ± [2 sqrt(3)]