The teacher will be very surprised to see your correct solution 😉
a*x^2 + b*x + c = 0
D = b^2 - 4 * a * c =
(-5)^2 - 4 * (1) * (3) = 13
x1 = (-b + sqrt(D)) / (2*a)
x2 = (-b - sqrt(D)) / (2*a)
____ 5 \/ 13 x1 = - - ------ 2 2
____ 5 \/ 13 x2 = - + ------ 2 2
x2 = sqrt(13)/2 + 5/2
sum
____ ____ 5 \/ 13 5 \/ 13 - - ------ + - + ------ 2 2 2 2
=
5
product
/ ____\ / ____\ |5 \/ 13 | |5 \/ 13 | |- - ------|*|- + ------| \2 2 / \2 2 /
=
3
3