So I assume you are trying to find the equation of the line.
So you are gonna use this equation:
y=mx+b
So the x and y are your x and y coordinate pair and the m is the slope. So now you just substitute and solve for b:
4=8(7)+b
4=56+b
subtract 56 on both sides
-52=b
so now lets plug this into the equation of the line:
y=8x+(-52)
hope this helps!