How to create inverse matrix with echelon form? Basis of subspace

Question

I need your help with 2 tasks. I totally do not know how to do them.

1. For matrix A, find the inverse matrix by fetching to echelon form. Use the block matrix() function to connect the matrices. Matrix is:

 1  3  0 -1
 0  2  1  3
 3  1  2  1 
-1  2  0  3 

2. Consider a subspace S generated by vectors:

v1=[1,0,3],v2=[0,2,2],v3=[1,-2,0].

Are they a basis of the subspace S?

I need code, because I haven't got a clue how to do that. Please, help