A census study shows that the population from 1990 to 1998 of the only large town in a certain county can be modeled by the formula 102 t ²– 225 t+ 3090 where t= 0 represents the year 1990 and that over the same years, the population of the surrounding county (not including the town) can be modeled by the formula 125 t ²+ 72 t+ 4978 where t= 0 represents the year 1990.  Find a model for the total population of the county during the years 1990 to 1997.