Question

A student found the slope of a line that passes through the points (2 , 16) and (5 , 4) to be -1/4 (fraction) . What mistake did he make ?

Answer 1

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 :)

Answer 2

Did he apply the slope formula correctly?

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

Hope this helps!