how do I solve this problem.

In 1920 the record for a certain race was 445.7 sec. In 1970, it was 44.2 sec. Let R(t) = the record in the race and t = the number of years since 1920.
a) Find a linear function that fits the data R(t) =
b) What is the predicted record for 2003?
c) What is the predicted record for 2006?
d) In what year will the predicted record be 42.70 seconds?