Evaluate the determinant of the given matrix by reducing the matrix to row-echelon form.
=[1 -2 -3 -5]
[ 4 -7 -6 4]
[-1 2 6 -3]
[2 4 -6 2]
det()=______.)
=[1 -2 -3 -5]
[ 4 -7 -6 4]
[-1 2 6 -3]
[2 4 -6 2]
det()=______.)