This matrix is said to be quickly solvable but im not sure of the trick:
-1 1 1 1 1
1 -1 1 1 1
1 1 -1 1 1
1 1 1 -1 1
1 1 1 1 -1
the matrix is all 1's with -1's on the main diagonal, im not sure if i should row reduce until i have an upper triangular matrix and use product of diagonal entries or if there is a simple trick im missing
Additional Details
the answer is 48 according to my ti-89