Question

Evaluate the determinants in Exercises 1 and 2.

$\begin{vmatrix}2&4\\\\-5&-1\end{vmatrix}$

Answer 1

$\begin{vmatrix}2&4\\\\-5&-1\end{vmatrix}=$ = 2(−1) − 4(−5) = − 2 + 20 = 18