"Find the points on the surface 4x^2+5y^2+5z^2=1 at which the tangent plane is parallel to the plane 4x-37-1z=-2" Im very lost when it comes to this problem. I know that if the planes are parallel, the normal vectors will be parallel. So I think I need to multiply plane (4x-37-1z=-2)'s normal vector by some consistent? Im not really sure what to do, nor do I understand the concept. Any help would be appreciated.