Plane1 := x + y -z = 2; Plane2 := 2*x - y + 3*z = 1; Line := solve({Plane1,Plane2},{x,y,z}); Point := vector([-1,2,1]); p1 := subs(z=0,Line); p2 := subs(z=1,Line); p1 := vector([1,1,0]): p2 := vector([1/3,8/3,1]): n := crossprod(p1-Point,p2-Point); r := vector([x,y,z]): ThePlane := innerprod(n, r-p1) = 0; sort(",[x,y,z]); sort(",[x,y,z]); "*3;