The teacher will be very surprised to see your correct solution 😉
a*y^2 + b*y + c = 0
D = b^2 - 4 * a * c =
(-4)^2 - 4 * (1) * (x^2 - 2*x) = 16 - 4*x^2 + 8*x
y1 = (-b + sqrt(D)) / (2*a)
y2 = (-b - sqrt(D)) / (2*a)
_______________________________________________________________ _______________________________________________________________ / 2 / / 2 2 \\ / 2 / / 2 2 \\ 4 / 2 / 2 2 \ |atan2\2*im(x) - 2*im(x)*re(x), 4 + im (x) - re (x) + 2*re(x)/| 4 / 2 / 2 2 \ |atan2\2*im(x) - 2*im(x)*re(x), 4 + im (x) - re (x) + 2*re(x)/| y1 = 2 - \/ (2*im(x) - 2*im(x)*re(x)) + \4 + im (x) - re (x) + 2*re(x)/ *cos|-------------------------------------------------------------| - I*\/ (2*im(x) - 2*im(x)*re(x)) + \4 + im (x) - re (x) + 2*re(x)/ *sin|-------------------------------------------------------------| \ 2 / \ 2 /
_______________________________________________________________ _______________________________________________________________ / 2 / / 2 2 \\ / 2 / / 2 2 \\ 4 / 2 / 2 2 \ |atan2\2*im(x) - 2*im(x)*re(x), 4 + im (x) - re (x) + 2*re(x)/| 4 / 2 / 2 2 \ |atan2\2*im(x) - 2*im(x)*re(x), 4 + im (x) - re (x) + 2*re(x)/| y2 = 2 + \/ (2*im(x) - 2*im(x)*re(x)) + \4 + im (x) - re (x) + 2*re(x)/ *cos|-------------------------------------------------------------| + I*\/ (2*im(x) - 2*im(x)*re(x)) + \4 + im (x) - re (x) + 2*re(x)/ *sin|-------------------------------------------------------------| \ 2 / \ 2 /
y2 = i*((-2*re(x)*im(x) + 2*im(x))^2 + (-re(x)^2 + 2*re(x) + im(x)^2 + 4)^2)^(1/4)*sin(atan2(-2*re(x)*im(x) + 2*im(x, -re(x)^2 + 2*re(x) + im(x)^2 + 4)/2) + ((-2*re(x)*im(x) + 2*im(x))^2 + (-re(x)^2 + 2*re(x) + im(x)^2 + 4)^2)^(1/4)*cos(atan2(-2*re(x)*im(x) + 2*im(x), -re(x)^2 + 2*re(x) + im(x)^2 + 4)/2) + 2)