The matrix given is [tex] \left[\begin{array}{ccc}-5&1\\1&4\end{array}\right] [/tex]
To find determinant [tex] \left[\begin{array}{ccc}a&b\\c&d\end{array}\right] [/tex] we do [tex]ad-bc[/tex]
So, the determinant of the given matrix is
[tex](-5)(4)-(1)(4) = -20 - 4 = -24[/tex]
