The answer is C.
Explanation:
(First, make sure the to finish solving the quadratic equation)
x^2 + 2x - 16 = 12x
x^2 - 10x - 16 = 0
(a, b and c are the coefficients of x^2, x and the constant respectively)
a = 1, b = -10, c = -16
(We can substitute this into the quadratic equation. +- means + or -)
x = [- b +- sqrt(b^2 - 4ac)]/2a
= [- (-10) +- sqrt(100 + 64)]/2
= [10 +- sqrt(164)]/2
(So C is the answer)
