#y=mx+b#
#m# = slope
#b# = y-intercept (where the line crosses the x-axis)
go up to #4# on the #y# axis (4,0). That is one of the points. From that point, which is #(4,0)#, use the slope and graph the next point, so the slope is #m#, which is #1/2#. The numerator ("#1#") states how much you go up or down (positive (+) up, negative (-) down). so in this case, you go up one on the y-axis. Then from that point go #2# points to the right (you get this from the denominator of #1/2#) if there is no denominator (ex: y=5x+1), there is always a #1# underneath every number (#y=5/1 x+1#).