Evalute the determinant: :
`[{:(2,4),(-5,-1):}]`

Explanation

To evaluate the determinant of the given matrix \( A = \begin{pmatrix} 2 & 4 \\ -5 & -1 \end{pmatrix} \), we can follow these steps:

### Step 1: Identify the elements of the matrix
The matrix \( A \) is a 2x2 matrix with the following elements:
- \( a = 2 \) (first row, first column)
- \( b = 4 \) (first row, second column)
- \( c = -5 \) (second row, first column)
- \( d = -1 \) (second row, second column)
...