Problem2:Find the system of linear equations corresponding to the augmented matrix 
> ;
[3 0 2 5] [ ] [7 1 4 3] [ ] [0 2 1 7]

This is a 3 by 4 matrix so it corresponds to a system with 3 equtaions in 3 unknowns (x,y,z) say. Using the matrix we obtain the system, 
> ;
3 x  2 z = 5 7 x + y + 4 z = 3 2 y + z = 7