Question

$\left|\begin{array}{cc}2x& 7\\ 3& 1\end{array}\right|=23$
Find the value of x?

• A. 4
• B. 3
• C. 7
• D. 1

Answer 1

The correct option is A 4

$\left|\begin{array}{cc}2x& 7\\ 3& 1\end{array}\right|=23$

$\Rightarrow 2x\times 1-21=23$
$\Rightarrow 2x-21=23$
$\Rightarrow 2x=23+21$
$\Rightarrow 2x=44$
$\Rightarrow x=\frac{44}{2}$
$\Rightarrow x=22$