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Answer:
C. 3
Explanation:
AD is perpendicular to BC, so its slope will be the opposite of the reciprocal of the slope of BC.
The slope of BC can be found from the slope formula:
m = (y2 -y1)/(x2 -x1)
m = (-1 -2)/(3 -(-6)) = -3/9 = -1/3
Then the slope of AD is ...
-1/(-1/3) = 3