Your line passes through (0,1) and (1,5). This means that the increase of 1 along the x axis results in an increase of 4 along the y axis. In other words, the slope is 4.
Since the y intercept is 1, the equation of the line is
[tex]y=4x+1[/tex]
(using the [tex]y=mx+b[/tex] form, where m is the slope and b is the y intercept).
Since we are interested in the area above the line, and the line is not included, we want the points with y coordinates strictly greater than those of the points on the line:
[tex]y>4x+1[/tex]
