+130518 4n^2-16n-14=6 add 14 to both sides
4n^2 - 16n = 20 divide through by 4
n^2 - 4n = 5 take (1/2) of (-4) = (-2)....square it = 4 and add to both sides
n^2 - 4n + 4 = 5 + 4 factor the left side, simplify the right
(n - 2) (n -2) = 9
(n - 2)^2 = 9 take the positive and negative roots of both sides
n - 2 = (plus/minus)( 3)
So
n - 2 = 3 and n = 5 or
n - 2 = -3 and n = -1
