The teacher will be very surprised to see your correct solution 😉
a*x^2 + b*x + c = 0
D = b^2 - 4 * a * c =
(1)^2 - 4 * (1) * (-36) = 145
x1 = (-b + sqrt(D)) / (2*a)
x2 = (-b - sqrt(D)) / (2*a)
sum
_____ _____ 1 \/ 145 1 \/ 145 - - + ------- + - - - ------- 2 2 2 2
=
-1
product
/ _____\ / _____\ | 1 \/ 145 | | 1 \/ 145 | |- - + -------|*|- - - -------| \ 2 2 / \ 2 2 /
=
-36
-36
_____ 1 \/ 145 x1 = - - + ------- 2 2
_____ 1 \/ 145 x2 = - - - ------- 2 2
x2 = -sqrt(145)/2 - 1/2