[tex] A (0,3), \ \ B (-3,0) \\\\\\ First \ find \ the \ slope \ of \ the \ line \ thru \ the \ points \: \\ \\ m= \frac{y_{2}-y_{1}}{x_{2}-x_{1} } \\ \\m=\frac{ 0-3}{-3-0} = \frac{-3}{-3}=1 \\ \\ Use \ point \ form \ of \ a \ line\ with \ one \ point: \\ \\ y-y_{1} =m(x-x _{1}) \\ \\m=1,\ \ x_{1}=0, \ \ y_{1}=3 \\ \\ y-3= (x-0}\\\\y= x +3 [/tex]