Question

(x-7(x^2-40=0

Answer 1

Viết lại đề đi, khó hiểu quá

Answer 2

\(\left(x-7\right)\left(x^2-4\right)=0\\ \Rightarrow\left(x-7\right)\left(x-2\right)\left(x+2\right)=0\\ \Rightarrow\left[{}\begin{matrix}x-7=0\\x-2=0\\x+2=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=7\\x=2\\x=-2\end{matrix}\right.\)

Answer 3

\((x-7)(x^2-40) = 0 \)

\(\Leftrightarrow ( x - 7 ) ( x + 2 ) ( x - 2 ) = 0 \)

\(\Leftrightarrow\left[\begin{matrix} x-7=0\\ x-2=0\\x+2=0\end{matrix}\right.\)

\(\Leftrightarrow\left[\begin{matrix} x=7\\ x=2\\x=-2\end{matrix}\right.\)

Vậy \(x \in \) { \(7 ; \pm2\) }