Question

Tìm số nguyên x, biết:

Answer 1

\(\left(3x-1\right)^2=64\)
\(\xrightarrow[]{}\left(3x-1\right)^2=8^2\)
\(\xrightarrow[]{}\left\{{}\begin{matrix}3x-1=8\\3x-1=-8\end{matrix}\right.\)

\(\xrightarrow[]{}\left\{{}\begin{matrix}x=3\\x=-\dfrac{7}{3}\end{matrix}\right.\)

Answer 2

`(3x-1)^2 =64`

`=> (3x-1)^2 =8^2`

\(\Rightarrow\left[{}\begin{matrix}3x-1=8\\3x-1=-8\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}3x=9\\3x=-7\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=2\\x=-\dfrac{7}{3}\end{matrix}\right.\)

vậy \(x\in\left\{2;-\dfrac{7}{3}\right\}\)