Answer:
y = (-1/3)x - 7
or
y + 8 = (-1/3)(x - 3)
Explanation:
First, find the slope (rise over run):
Δy / Δx = (-8 + 9) / (3 - 6) = 1 / -3 = -1/3
Then use one of the given points to put it into point-slope form:
y + 8 = (-1/3)(x - 3)
or optionally in slope-intercept form:
y = (-1/3)x - 7