pick 2 points off ur line...it is easier if u pick whole number points
(2,0) and (0,5)
slope formula = (y2 - y1) / (x2 - x1)
now label ur points
(2,0)...x1 = 2 and y1 = 0
(0,5)...x2 = 0 and y2 = 5
now sub and find the slope
slope(m) = (5 - 0) / (0 - 2) = -5/2 <====