Question 389010
M[10,5:6,12]

These are both valid notations for the determinant of a matrix.
detM[10,5:6,12]=M[D,10,5:6,12]

The determinant of a 2x2 matrix can be found using the formula M[D,a,b:c,d]=ad-cb
detM[10,5:6,12]=(10)(12)-(6)(5)

Simplify the determinant.
detM[10,5:6,12]=90

The determinant of M[10,5:6,12] is 90.
90



The determinant of matrix A is given by 

det(A) = a*d - c*b