Tìm x, biết: x^4 + 10x^3 + 35x^2 + 50x + 24 = 0.
Giải thích
x4 + 10x3 + 35x2 + 50x + 24 = 0
x4 + x3 + 9x3 + 9x2 + 26x2 + 26x + 24x + 24 = 0
(x + 1)(x3 + 9x2 + 26x + 24) = 0
(x + 1)( x3 + 2x2 + 7x2 + 14x + 12x + 24) = 0
(x + 1)(x + 2)(x2 + 7x + 12) = 0
(x + 1)(x + 2)(x2 + 3x + 4x + 12) = 0
(x + 1)(x + 2)(x + 3)(x + 4) = 0
Vậy x {–1; –2; –3; –4}.