What number goes in the box so that
\[x^2 + \boxed{\phantom{00}}x + 4\]
is the square of a binomial? If you find more than one, give your answer as a list.
Try expanding (x+2)^2 and (x-2)^2 and see what you get. :))
=^._.^=
Let the middle term = bx
Completing the square on this term would give us
(b / 2)^2 = 4
b^2 / 4 = 4
b^2 = 16 take both roots
b = 4 or b = -4
