If $\begin{vmatrix} 2x & 5 \\ 8 & x \end{vmatrix} = \begin{vmatrix} 6 & -2 \\ 7 & 3 \end{vmatrix}$, then the value of $x$ is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → $\pm 6$ ##
We have, $\begin{vmatrix} 2x & 5 \\ 8 & x \end{vmatrix} = \begin{vmatrix} 6 & -2 \\ 7 & 3 \end{vmatrix}$
$\Rightarrow 2x^2 - 40 = 18 + 14$
$\Rightarrow 2x^2 = 32 + 40$
$\Rightarrow x^2 = \frac{72}{2} = 36$
$∴x = \pm 6$