If $\left| \begin{matrix}
3 & \phantom{-}x \\
x & 1 \\
\end{matrix} \right|$
$=$
$\left| \begin{matrix}
3 & \phantom{-}2 \\
4 & 1 \\
\end{matrix} \right|$ then the value of $x$ is equa to
Karnataka PU MQP 2023, MQP2014
Solution
The correct answer is $\pm 2 \sqrt{2}$
Explanation
We have $\left| \begin{matrix}
3 & \phantom{-}x \\
x & 1 \\
\end{matrix} \right|$ $=$
$\left| \begin{matrix}
3 & \phantom{-}2 \\
4 & 1 \\
\end{matrix} \right|$