Answer
$\pm 2$
Work Step by Step
The determinant of a $2 \times 2$ matrix can be computed by using the formula $det =ps-qr$
where $det =\begin{bmatrix}p & q \\
r & s\end{bmatrix}$
After simplifying, this matrix yields: $2 =(x)(x) - (2)(1) $
or, $x^2-2=2 \implies x=\pm 2$
