r1:2*x-6*y+4*z=0; r2:-x+3*y-2*z=0;

linsolve([r1,r2],[x,y,z]);

load(draw)$

draw3d(xaxis=true,yaxis=true,zaxis=true,color=red,implicit(r1,x,-10,10,y,-10,10,z,-10,10),implicit(r2,x,-10,10,y,-10,10,z,-10,10));

r3:2*x-6*y+4*z=2; r4:-x+3*y-2*z=-1;

linsolve([r3,r4],[x,y,z]);

draw3d(xaxis=true,yaxis=true,zaxis=true,color=blue,implicit(r3,x,-10,10,y,-10,10,z,-10,10),implicit(r4,x,-10,10,y,-10,10,z,-10,10));

draw3d(surface_hide=true,xaxis=true,yaxis=true,zaxis=true,color=red,implicit(r1,x,-5,5,y,-5,5,z,-5,5),implicit(r2,x,-5,5,y,-5,5,z,-5,5),color=blue,implicit(r3,x,-5,5,y,-5,5,z,-5,5),implicit(r4,x,-5,5,y,-5,5,z,-5,5));