When an euation has infinitely solutions or has no solutions?

See:

https://www.askmehelpdesk.com/math-sciences/equations-infinite-no-solutions-235091.html

one of the answer and the evergreen method to find the solution and the number of solutions is to draw the GRAPH of the given equation. I don't have a link but you must check the method of drawing graphs, you can solve 90% of questions using graph only!