x³ + 4x² = -3x
x³ + 4x² + 3x = 0
x(x² + 4x + 3) = 0
x = 0 v x² + 4x + 3
∆ = 4² + 4 * 1 * 3 = 16 - 12 = 4
√∆ = √4 = 2
x = (-4 - 2)/(2 * 1) = -3
x = (-4 + 2)/(2 * 1) = -1
x = {-3, -1, 0}
x³ - 4x² + 3x - 12 = 0
x²(x - 4) + 3(x - 4) = 0
(x² + 3)(x - 4) = 0
x² + 3 = 0 (sprzeczność) v x - 4 = 0
x = 4
