Question

tìm x

x⁴+x^3_27x^_27=0

Answer 1

\(x^4+x^3-27x-27=0\)

\(\Leftrightarrow x^3\left(x+1\right)-27\left(x+1\right)=0\)

\(\Leftrightarrow\left(x+1\right)\left(x^3-27\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x+1=0\\x^3=3^3\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=3\end{matrix}\right.\)