Question

Show that set of all the invertible matrices of order (n*m) with determinant 1,-1 form a group under multiplication

Answer 1

i believe invertible matrices implies it is square

Answer 2

so the order should be n*n

Answer 3

and this is a subgroup of the general linear group , I would think.

Answer 4

and you want the special linear group
The special linear group, written SL(n, F) or SLn(F), is the subgroup of GL(n, F) consisting of matrices with a determinant of 1.

Answer 5

you will have to say something, or i leave