Question 1194503
With 16 officers, one would expect 19.2 arrests, since 16*1.2 is 19.2
The actual rate is 36, so there is a 36-19.2=16.8 arrests that are built into the function without officers. That is the intercept.

R=1.2x+16.8
The intercept suggests the rate if there are no officers. Intercepts that are outside of the sensible domain are often do not makes sense. 

The range is (16.8, 100), since this is per cent.
For the domain, R cannot be >100, so 100=1.2x+16.8, and x=69.3 or 69 officers
The domain is (1, 69.3) using 1 as a low bound since presumably 0 officers would not be a department.

{{{graph(300,300,-5,70,-10,110,1.2x+16.8)}}}