(-6,6)(12,3)
slope(m) = (3 - 6) / (12 - (-6) = -3 / 18 = -1/6
y = mx + b
slope(m) = -1/6
use eitehr of ur sets of points...(12,3),,,x = 12 and y = 3
now sub and find b, the y int
3 = -1/6(12) + b
3 = -12/6 + b
3 = -2 + b
3 + 2 = b
5 = b <===
and ur equation is : y = -1/6x + 5