**1.3.1. Linear relationships and their graphs**

Identify linear equations such as \(ax=k\) or \(ax+by=k\).

Describe graphs of linear equations in two variables in the forms \(y=mx+c\), \(y-y_0=m(x-x_0)\) and \(ax+by=c\).

See graphically why a system of two linear equations in 2 variables may have no solutions, one unique solution of infinitely many solutions.