[tex]\bf \begin{array}{|c|ll} \cline{1-1} slope-intercept~form\\ \cline{1-1} \\ y=\underset{y-intercept}{\stackrel{slope\qquad }{\stackrel{\downarrow }{m}x+\underset{\uparrow }{b}}} \\\\ \cline{1-1} \end{array}~\hspace{7em}y=5x+8[/tex]
to graph a line, all you need is two points, so, we know the y-intercept is at 8, namely the graph touches or intercepts the y-axis at 8, so that's one point, (0,8).
let's get another point, a random "x", say x = -2, y = 5(-2)+8 => y = -2, so (-2, -2).
check the picture below.
