Answer:
60
Step-by-step explanation:
We have been given the matrix;
[tex]\left[\begin{array}{ccc}5&8\\-5&4\end{array}\right][/tex]
For a 2-by-2 matrix, the determinant is calculated as;
( product of elements in the leading diagonal) - (product of elements in the other diagonal)
determinant = ( 5*4) - (8*-5)
= 20 - (-40) = 60