y = x^2 - 2x - 1
p = -b/2a = 2/2 = 1
q = f(p) = 1^2 - 2*1 - 1 = 1 - 2 - 1 = -2
postac kanoniczna: y = (x - 1)^2 - 2
delta = 4 + 4 = 8
p(delta) = p(8) = 2p(2)
x1 = (2 + 2p(2))/2 = 1 + p(2)
x2 = (2 - 2p(2))/2 = 1 - p(2)
postac iloczynowa: y = (x - 1 - p(2))(x - 1 + p(2))
