Question

Answer 1

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

Answer 2

b)x³-9x=0

⇔x(x²-9)=0

⇔x(x-3)(x+3)=0

⇔x=0 hay x-3=0 hay x+3=0

⇔x=0 hay x=3 hay x=-3