Question

giúp em với ạ ! em cần gấp

Answer 1

\(\Leftrightarrow3x^4-9x^3+9x^2-27x=0\)

\(\Leftrightarrow x\left(3x^3-9x^2+9x-27\right)=0\\ \Leftrightarrow x\left[\left(3x^3-9x^2\right)+\left(9x-27\right)\right]=0\\ \Leftrightarrow x\left[3x^2\left(x-3\right)+9\left(x-3\right)\right]=0\\ \Leftrightarrow x\left(3x^2+9\right)\left(x-3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x^2=-3\left(vôlí\right)\\x=3\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=3\end{matrix}\right.\)