Question

Разложите на множители
х^3-2х^2-5х+6

Answer 1

  x³ - 2x² - 5x + 6 = x³ - 4x² + 3x + 2x² - 8x + 6 =

= x(x² - 4x + 3) + 2(x² - 4x + 3) = (x + 2)(x² - 4x + 3) = (x + 2)(x - 1)(x - 3);

x² - 4x + 3 = 0       D = b²-4ac = 16-12 = 4

x = (-b±√D)/2a

x₁ = 3

x₂ = 1