Question

Could someone please tell me which property of matrix is this? And how is it derived? - "For any 4-by-4 matrix that has a row of 1's along the bottom, you can compute the determinant with a simplification formula that reduces the problem to a 3-by-3 matrix".

Answer 1

Try doing something similar with turning a 3x3 matrix with a row of all 1s on the bottom into a 2x2 matrix problem and see if you can't figure it out.