Respuesta :

Did he apply the slope formula correctly?

y2-y1    (16-4)
--------              = 12/-3 = -4
x2-x1    (2-5)

Hope this helps!
slope = m = (change in y)/(change in x)
slope = (4-16)/(5-2) = -12/3 = -4

He got the reciprocal of the correct answer, so he must have mistakenly calculated slope as a (change in x)/(change in y).

hope this helps :)