Question 607697
Look up the following website: http://en.wikipedia.org/wiki/Determinant


Basically the determinant is 8*det(A) - 1*det(B) + 3*det(C)


where A,B,C are the matrices determined by truncating every entry in the same column or row as 8, 1, 3. In other words,


A = {{-1,4}{-1,2}}
B = {{2,-4}{1,2}}
C = {{2,-1}{1,-1}}


Finding the determinant of a 2x2 matrix should be easy.