Answer
Please see step-by-step.
Work Step by Step
A second order determinant has two rows and two columns.
To evaluate,
find the difference of the products of diagonals.
(Top left $\times$ bottom right) - (top right $\times$ bottom left),
or, $\left|\begin{array}{ll}
a & b\\
c & d
\end{array}\right|=ad-bc$
