Determinan dari $$$\left[\begin{array}{cc}1 & 2\\7 & 8\end{array}\right]$$$

Hitung $$$\left|\begin{array}{cc}1 & 2\\7 & 8\end{array}\right|$$$.

Determinan matriks 2x2 adalah $$$\left|\begin{array}{cc}a & b\\c & d\end{array}\right| = a d - b c$$$.

$$$\left|\begin{array}{cc}1 & 2\\7 & 8\end{array}\right| = \left(1\right)\cdot \left(8\right) - \left(2\right)\cdot \left(7\right) = -6$$$

$$$\left|\begin{array}{cc}1 & 2\\7 & 8\end{array}\right| = -6$$$A