Solve the assigned system of linear equations, then type the lines equations in the [i]r[/i] and [i]s[/i] fields (press Enter to confirm each input), in order to view the graphical solution of the system.

Why is this kind of system named [i]linear[/i] ?[br]Which conditions allow you to decide [i]a priori[/i] whether a system has [i]a single unique solution / infinitely many solutions / no solution[/i] ?[br][br]Write down on paper the equations of a system having a single unique solution, one with infinitely many solutions, and one having no solution.