\(x^4+x^3+6x^2=-5x-5\)
\(\Leftrightarrow x^4+x^3+6x^2+5x+5=0\)
\(\Leftrightarrow x^4+x^3+x^2+5x^2+5x+5=0\)
\(\Leftrightarrow x^2\left(x^2+x+1\right)+5\left(x^2+x+1\right)=0\)
\(\Leftrightarrow\left(x^2+x+1\right)\left(x^2+5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x^2+x+1=0\\x^2+5=0\end{matrix}\right.\) (vô nghiệm)
Vậy PT trên vô nghiệm