> solve({x+y=2,2*x+2*y=4}, {x,y});

                         {x = -y + 2, y = y}

> Pi;

                                  Pi

> evalf(Pi,100);

  3.14159265358979323846264338327950288419716939937510582097494459\
        2307816406286208998628034825342117068

> solve({x+y+z=1,x+y+z=2},{x,y,z});
>