For years of 1980 to 1990, the number of mountain owners m ( in millions ) in the US can be approximated by the model m=.377t^2 – 2.265t + 3.962,3 ≤ t ≤ 10 where t = 3 represents 1983.
1. In which year did 2.5 million people own mountain bikes?
2. In what year was the number of mountain bike owners at a minimum?

I’ll really appreciated if it’s was posible to explain how did you got the answer. Thank you