Median Household Income: In 1980, median family income was about $18,000, and in 2000 it was about $42,000 ...

Median Household Income: In 1980, median family income was about $18,000, and in 2000 it was about $42,000.
 

(a) Find the slope of the line passing through the points (1980, 18000) and (2000, 42,000).
 

(b) Interpret the slope as a rate of change.
 

(c) If this trend continues, estimate the median family income in 2005.