Quadratic, Cubic, equations

https://shkolkovo.net/theory/108

2x^2-9x+7=0 where (a + b +c) = 0

1, 3,5 = c/a

2x^2+9x+7=0 where (a + b +c) <> 0 b = a + c

-1, -3.5 = -c/a

2x^2 -7x -9 =0 (a  + b + c) <> 0

-1, 4.5 = -c/a

-13x^2 -5x +18=0

1, -18/13

-13x^2+5x+18=0

-1, -18/13

https://www.youtube.com/watch?v=LKGtbQZzBuo&t=8s

https://www.mathway.com/ru/popular-problems/Algebra/230840