Найду корень уравнения: x²-8x-9=0
2 x - 8*x - 9 = 0
a*x^2 + b*x + c = 0
D = b^2 - 4 * a * c =
(-8)^2 - 4 * (1) * (-9) = 100
x1 = (-b + sqrt(D)) / (2*a)
x2 = (-b - sqrt(D)) / (2*a)
x1 = -1
x2 = 9
x1 = 9.0
x2 = -1.0