First find slope=m=(y2-y1)/(x2-x1). In this case:
(-2-1)/(2-4)=m=-3/-2
m=1.5, and since we are making a line of the form y=mx+b we have so far:
y=1.5x+b, now using either point, (2,-2) we can solve for b, the y-intercept:
-2=1.5(2)+b
-2=3+b
b=-5
So our line is:
y=1.5x-5