help please
in 1920 the record for a certain race was 45.9 seconds. In 1960 it was 44.7 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
b. use the function in (a) to predict the record in 2003 and in 2006
c. find the year when the record will be 43.26 sec.
round to nearest hundredth

Question

help please
in 1920 the record for a certain race was 45.9 seconds.  In 1960 it was 44.7 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
b.  use the function in (a) to predict the record   in 2003 and in 2006
c. find the year when the record will be 43.26 sec. 
round to nearest hundredth

dumbcow · Answer

use 2 points (t,R)
(0,45.9) and (40,44.7)
slope = (44.7-45.9)/(40-0) = -1.2/40 = -.03
y_intercept is when t=0: (0,45.9)

R(t) = -.03t + 45.9

anonymous · Answer

hi dumbcow what is the ans to the other two questions b and c

dumbcow · Answer

use R(t) and substitute in t=83 and t=86
for part c
43.26 = -.03t +45.9
solve for t

anonymous · Answer

what year will the record be 43.26 sec

dumbcow · Answer

get t by itself
1) subtract 45.9 on both sides
2) divide by -.03 on both sides

anonymous · Answer

I'm very confuse now

dumbcow · Answer

do you know how to solve linear equations?
like
4x -2 = 10
solve for x

anonymous · Answer

no i do not

dumbcow · Answer

well that would help you with this question and class im guessing...
t=88
this means 88 years after 1920
=2008

anonymous · Answer

that helped me thank you very much