(x-3)(2x+2)=(x-3)(x²-6)
(x-3)(2x+2) - (x-3)(x²-6) = 0
(x - 3) [ (2x + 2) - (x² - 6) ] = 0
x - 3 = 0 lub 2x +2 - x² + 6 = 0
x = 3 -x² + 2x + 8 = 0
x² - 2x - 8 = 0
Δ = 4 - 4 * 1 * (-8) = 4 + 32 = 36
√Δ = 6
x1 = (2 - 6)/2 = -4/2 = -2
x2 = (2 + 6)/2 = 8/2 = 4
odp. x = 3 lyb x = -2 lub x = 4