Question

EXPONENTIAL GROWTH AND DECAY HELP PLEASE, DUE TODAY:(
Use the following information and y = a x b^x to find during what year Chessville's population will first exceed Checkersville's.
INFO:
January.10.2010- Chessville has a population of 50,000 people. The population increases 7% every year.
January.10.2010 (same day)- Checkersville has a population of 70,000 people. The population decreases 4% every year.

During what year will Chessville's population first exceed Checkersville's?