Помогите решить уравнение

x^4+5x^3+5x^2-5x-6=0

X^4+5*x^3+5x^2-5x-6=0 (x^4-1) + 5*x^2 (x+1) - 5 * (x+1) = 0 (x^2+1) * (x-1) * (x+1) + 5*x^2 * (x+1) - 5 * (x+1) = 0 (x+1) * ((x^2+1) * (x-1) + 5*x^2-5) = 0 (x+1) * ((x^2+1) * (x-1) + 5 * (x-1) * (x+1)) = 0 (x+1) * (x-1) * (x^2+5x+6) = 0 (x+1) * (x-1) * (x+2) * (x+3) = 0 x1=1 x2=-1 x3=-2 x4=-3