Compare that equation to



and you'll see that m = the slope =  and b=8 and the 
y-intercept is the point (0,b) = (0,8).  We plot the y-intercept,
(0,8):

 

Starting at that y-intercept we take the NUMERATOR of the slope,
which is 5, and draw a VERTICAL line 5 units long UPWARD, since 
the slope is positive (it would be downward if the slope were 
negative), like the green arrow below:



Now from that arrowhead, we turn RIGHT and draw a HORIZONTAL line
equal to the number of units indicated by the DENOMINATOR of the slope, 
that is, 3 units, like the green horizontal line below:



To make the graph, we draw a line through the end of the horizontal
line and the y-intercept (0,8), like this:



That red line is the graph of the equation .

Edwin