slope = rise / run
m = (y2 - y1) / (x2 - x1)
(8, -4); (-7, 9)
m = (9 - -4) / (-7 - 8) = -13/15
point-slope: y - 9 = (-13/15) (x + 7)
y - 9 = (-13/15)x - 91/15
y = (-13/15)x + 44/15 (slope-intercept form)
(4, -2); (-6,6)
m = (6 - -2) / (-6 - 4) = -4/5
point-slope: y + 2 = (-4/5) (x -4)
y + 2 = (-4/5)x + 16/15
y = (-4/5)x - 14/15 (slope-intercept form)
(3,0); (0,8)
m = (8 - 0) / (0 - 3) = -8/3
point-slope: y - 8 = (-8/3) (x - 0)
point-slope: y - 8 = (-8/3) x
slope-intercept: y = (-8/3)x + 8