Question

Rozwiąż równanie: 9x³ + 18x² - 4x - 8 = 0.

Answer 1

9x³ + 18x² - 4x - 8 = 0

9x²(x + 2) - 4(x + 2) = 0

(x + 2)(9x² - 4) = 0

(x + 2)(3x + 2)(3x - 2) = 0

x+2 = 0    lub    3x+2 = 0    lub    3x-2 = 0

x = -2        v      3x = -2        v      3x = 2 

x = -2        v      x = -2/3      v      x = 2/3

x ∈ {-2; -2/3; 2/3}

Answer 2

Więc;
9x3+18x2-4x-8=0
9x2(x+2)-4(x+2)=0
(9x2-4)(x+2)=0
(3x-2)(3x+2)(x+2)=0
x=2/3
x=-2/3
x=-2
--------------------------