\(x^2-1=2^2.12\)
\(\Rightarrow x^2-1=4.12\)
\(\Rightarrow x^2-1=48\)
\(\Rightarrow x^2=48+1\)
\(\Rightarrow x^2=49\)
\(\Rightarrow\left[{}\begin{matrix}x=7\\x=-7\end{matrix}\right.\)
Vậy \(x\in\left\{7;-7\right\}.\)
Chúc bạn học tốt!
(x^2)-1=(2^2).12
(x^2)-1=4.12
(x^2)-1=48
x^2=48+1
x^2=49
suy ra;x^2=7^2
suy ra;x=7