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
<span>а) 4c(a-c)+7c(a-c)= (а -с)(4с +7с)</span>
<span /><span>б) xz+yz+5x+5y = z(x +y) +5(x +y) = ( x + y)(z + 5)</span>