You have the following equation:
Take into account that the general form is a line equation is:
y = mx + b
where m is the slope and b the y coordinate of the y-intercept.
As you can notice, by comparing the given equation with the general expression, you have:
m = -7/2
b = 0
In order to graph the line, you can calculate two points on the line and draw a straight line wich crosses the points. For instance, if x = 0 and x = 2, you have for y:
y = -7/2*(0) = 0
y = -7/2*(2) = -7
which means that (0,0) and (2,-7) are on the line.
Then, the graph can be represented as follow: