The teacher will be very surprised to see your correct solution 😉
/ 2 \ (x - 1)*\x + x + 1/ = 0
a*x^2 + b*x + c = 0
D = b^2 - 4 * a * c =
(1)^2 - 4 * (1) * (1) = -3
x2 = (-b + sqrt(D)) / (2*a)
x3 = (-b - sqrt(D)) / (2*a)
x1 = 1
___
1 I*\/ 3
x2 = - - - -------
2 2
___
1 I*\/ 3
x3 = - - + -------
2 2
x3 = -1/2 + sqrt(3)*i/2
sum
___ ___
1 I*\/ 3 1 I*\/ 3
1 + - - - ------- + - - + -------
2 2 2 2
=
0
product
/ ___\ / ___\ | 1 I*\/ 3 | | 1 I*\/ 3 | |- - - -------|*|- - + -------| \ 2 2 / \ 2 2 /
=
1
1
x1 = 1.0
x2 = -0.5 - 0.866025403784439*i
x3 = -0.5 + 0.866025403784439*i
x3 = -0.5 + 0.866025403784439*i