(y+20)=1(x+10); First, we can find the slope by using the equation y2-y1/x2-x1.
-9+20/1+10 (Accounting for double negatives).
11/11 = 1
The slope of the equation is 1, now we just need to pick a set of points from which we derived the slope from (doesn't matter which) as y1 and x1 in the point-slope equation. (y-y1)=m(x-x1)
Your final answer can either be (y+20)=1(x+10) or (y+9)=1(x-1) but in the context of this question it is (y+20)=1(x+10)