Answer:
Use points (4,1) and (3,-1)
Explanation:
Let's say the other coordinates are (x,y).
Then, we know (1-y)/(4-x)=2. So if y is -1, and x is 3, then we get:
[1-(-1)]/(4-3)=2/1=2
So draw the two points, (4,1) and (3,-1) on a coordinate plane, and use a ruler to make a line that goes through both the points.