(2,-5) move up three steps is (2, -2). if you draw it on a paper(and draw lines to connect them), you can see that they form a right triangle. apply a²+b²=c² and you should get 3²+2²=(√13)²
First find the slope of the line so change in y over change in x so 4-2/1-2 which is 2/-1 so -2 is your slope then plug that as well as a point from above to find your y intercept so y=mx+b 2=-2(2)+ b then you have 2=-4+b then add 4 to each side and you find b is six then you make ur equation from your slope and y int(b) y=-2x+6