p1:=plot3d([x,y,6+2*x+4*y],x=-3

p1:=plot3d([x,y,6+2*x+4*y],x=-3..3,y=-3..3,axes=framed):
p2:=plot3d([x, y,(5+(x-1)^2+(y+2)^2)],x=-3..3,y=-3..3,axes=framed,color=orange):
display({p1,p2});