use y2-y1/x2-x1 to find the slope so= -17-3/19-9=-20/10=-2
so once you find the slope take one of the points and plug it into the slope-int equation so... if you take (9,3) and take your slope (-2) so it would be: 3=-2(9)+b solve for b to get 21=b as your int. so.. y=-2x+21
