F (x) = x^2+4 solve using the quadratic formula

a = 1 b = 0 a = 4

x = [-b + -sq root (b^2 - 4ac) ] / 2a

x = [0 + - sq root (0 - 4 * 1 * 4) ] / 2a

x1 = + 4i / 2

x1 = 2i

x2 = - 4i / 2

x2 = - 2i

Where "i" is the square root of minus 1