Odpowiedź:
a)
(x - 8)(x + 1)(5x -3) =0
x - 8 = 0 ∨ x + 1 = 0 ∨ 5x - 3 = 0
x = 8 , x = - 1 , 5x = 3
x = 8 , x = - 1 , x = 3/5
b)
3x³ + 18x² + 15x = 0
3x(x² + 6x + 5) = 0
3x = 0 ∨ x² + 6x + 5 = 0
x = 0
x² + 6x + 5 = 0
a = 1 , b = 6 , c = 5
Δ = b² - 4ac = 6² - 4 * 1 * 5 = 36 - 20 = 16
√Δ = √16 = 4
x₁ = (- b - √Δ)/2a = ( - 6 - 4)/2 = - 10/2 = - 5
x₂ = (- b + √Δ)/2a = (- 6 + 4)/2 = - 2/2 = - 1
x = 0 ∨ x = - 5 ∨ x = - 1
c)
(x² - 4x + 4)(4 - x) = 0
(x - 2)²(4 - x) = 0
(x - 2)(x - 2)(4 - x) =0
x - 2 = 0 ∨ 4 - x = 0
x = 2 ∨ - x = - 4
x = 2 ∨ x = 4