The teacher will be very surprised to see your correct solution 😉
a*x^2 + b*x + c = 0
D = b^2 - 4 * a * c =
(4)^2 - 4 * (4) * (5) = -64
x1 = (-b + sqrt(D)) / (2*a)
x2 = (-b - sqrt(D)) / (2*a)
x1 = -1/2 - I
x2 = -1/2 + I
x2 = -1/2 + i
sum
-1/2 - I + -1/2 + I
=
-1
product
(-1/2 - I)*(-1/2 + I)
=
5/4
5/4