Answer
Three additional points on the line can be:
$(2,6)$
$(3,10)$
$(4,14)$
Work Step by Step
If we interpret the slope, we can say that if $m=4$, then for every $1$ unit increase in $x$, $y$ increases by $4$. Using that, we can calculate more points on the line.
The starting point is given $(1,2)$, after that, we have to add the aforementioned changes to the x and y-coordinates.
Next point can be:
$(1+1,2+4)=(2,6)$
Now, starting with $(2,6)$ we add the changes again:
$(2+1,6+4)=(3,10)$
Now, starting with $(3,10)$ we add the changes again:
$(3+1,10+4)=(4,14)$