The average poverty threshold for 1990-2011 for a single individual can be modeled by
y = - 4199.9 + 4436.3 ln x
where x is the number of years past 1980 and y is the annual income in dollars
(a) What does the model predict as the poverty threshold in 2018?
(b) Graph this function for x = 0 to x = 40 and y ≥ 0.