For no solution, the two lines have to never intersect, which means they have to be parallel lines. In other words, no solution will satisfy both equation. For infinitely many solutions, the two lines have to overlap each other, which means one equation has to be a multiple of the other equations.
[joint] the site of the junction or union of two or more bones of the body; its primary function is to provide motion and flexibility to the frame of the body. Some are immovable, such as the sutures where segments of bone are fused together in the skull.
The skull base comprises parts of the frontal, ethmoid, sphenoid, occipital and temporal bones. The face is referred to as all skull bones fronto-caudally connected to the cerebral cranium. Prominent representatives are the maxilla (upper jaw) and the mandible (lower jaw).