If $\left|\begin{array}{cc}2 x & 5 \\ 8 & x\end{array}\right|=\left|\begin{array}{cc}6 & -2 \\ 7 & 3\end{array}\right|$ then the value of x is:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → $\pm 6$
$\left|\begin{array}{cc}2 x & 5 \\ 8 & x\end{array}\right|=\left|\begin{array}{cc}6 & -2 \\ 7 & 3\end{array}\right|$
$⇒2x^2-40=18+14$
$x^2=20+9+7⇒x^2=36$
$x=\pm 6$