to get the equation of a line, let's first find its slope, now, we can get that from just two points off the line, hmmmmm say (0, -3) and (2, -2).
[tex]\bf (\stackrel{x_1}{0}~,~\stackrel{y_1}{-3})\qquad (\stackrel{x_2}{2}~,~\stackrel{y_2}{-2}) \\\\\\ slope = m\implies \cfrac{\stackrel{rise}{ y_2- y_1}}{\stackrel{run}{ x_2- x_1}}\implies \cfrac{-2-(-3)}{2-0}\implies \cfrac{-2+3}{2}\implies \cfrac{1}{2} \\\\\\ \begin{array}{|c|ll} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-(-3)=\cfrac{1}{2}(x-0) \\\\\\ y+3=\cfrac{1}{2}x\implies y=\cfrac{1}{2}x-3[/tex]
