x * y * z = -180
y = x + 3
z = x - 4
x * (x+3)(x-4) = -180
x(x² - 4x + 3x - 12) = -180
x(x² - x - 12) = -180
x³ - x² - 12x + 180 = 0
x³ - (x² + 12x) + 180 = 0
x³ - (x² + 12x + 36) + 36 + 180 = 0
x³ - (x+6)² + 216 = 0
x³ + 216 - (x+6)² = 0
(x+6)³-18x² -108x - (x+6)² = 0
(x+6)³ - 18x(x + 6) - (x+6)² = 0
(x+6)[(x+6)² - 18x - (x+6)] = 0
(x+6)(x² + 12x + 36 - 18x - x - 6) = 0
(x+6)(x² - 7x + 30) = 0
x + 6 = 0 ∨ x² - 7x + 30 = 0
x + 6 = 0
x = -6
x² - 7x + 30 = 0
Δ = 49 - 4*30 = 49-120 < 0
brak rozwiązań
x = -6
y = -6 + 3 = -3
z = -6-4 = -10
