y = -3x + 2x² - 2
y = 2x² - 3x - 2
a = 2, b = -3, c = -2
∆ = (-3)² - 4 * 2 * (-2) = 9 + 16 = 25
√∆ = √25 = 5
x = (-(-3) - 5)/(2 * 2) = -2/4 = -1/2
x = (-(-3) + 5)/(2 * 2) = 8/4 = 2
y = 2(x + 1/2)(x - 2) — postać iloczynowa
p = -b/2a = 3/4
q = -∆/4a = -25/8
y = 2(x - 3/4)² - 25/8 — postać kanoniczna