Linear systems

 

In Reduce

For comparison with other CAS choose from: Axiom Derive Macsyma Maple Mathematica

inputs outputs

    solve(2*x1+x2+3*x3-9,x1-2*x2+x3+2,3*x1+2*x2+2*x3-7, x1,x2,x3);

    {{x1=-1,x2=2,x3=3}}