to find two points that satisfy the function, you need to give one value and calculate the other one, for example.
I will use x=4 and x=8
when x=4
y=4-8=-4
so one point is (4,-4)
and when x=8
y=8-8=0
so the other point is (8,0)
so you need to graph these points and then plot the line, like this:
