The teacher will be very surprised to see your correct solution 😉
64*(x + y)*x 24 ------------ + 80*y = -- 64 25
a*x^2 + b*x + c = 0
D = b^2 - 4 * a * c =
(y)^2 - 4 * (1) * (-24/25 + 80*y) = 96/25 + y^2 - 320*y
x1 = (-b + sqrt(D)) / (2*a)
x2 = (-b - sqrt(D)) / (2*a)
_____________________ / 2 y \/ 96 - 8000*y + 25*y x1 = - - - ------------------------ 2 10
_____________________ / 2 y \/ 96 - 8000*y + 25*y x2 = - - + ------------------------ 2 10
sum
_____________________ _____________________ / 2 / 2 y \/ 96 - 8000*y + 25*y y \/ 96 - 8000*y + 25*y 0 + - - - ------------------------ + - - + ------------------------ 2 10 2 10
=
-y
product
/ _____________________\ / _____________________\ | / 2 | | / 2 | | y \/ 96 - 8000*y + 25*y | | y \/ 96 - 8000*y + 25*y | 1*|- - - ------------------------|*|- - + ------------------------| \ 2 10 / \ 2 10 /
=
24 - -- + 80*y 25
-24/25 + 80*y