For this case we have that by definition, the slope of a line is given by:

Where:
and
are two points through which the line passes.
According to the image we have:

Substituting we have:

Thus, the slope of the line is:

Answer:

F=4 and y=3 those are the answers
87 / 114 = x / 9918....87 people to 114 = x people to 9918
cross multiply
(114)9x) = (87)(9918)
114x = 862866
x = 862866/114
x = 7569 <===