you were given the initial point {t,a} of: {2009,311}
you can quickly calculate the point for next year: {2010, 283.2}

Now that you have two points, you can calculate the function that would draw a line between them, this function is the answer to part A.

Using the function from part A, substitute t = 2014 and solve for a, that is the answer to part B.

Using the function from part A, substitute a = 100 and solve for t, that is the answer to part C.

This post was edited by Azrad on Aug 28 2013 02:12pm

lost in part A
cant do B w/o A

Yeah if you don't know how to do part A, you are totally screwed. This should help:



oh in your problem a is y, and t is x... hehe

This post was edited by Azrad on Aug 28 2013 02:29pm

im so pissed
idk how to do this

we generally work with the equation for a line in the form y=mx+b
for your problem it would be a = mt+b

m is the slope

slope = m = Δy/Δx

for your problem it would be:
slope = m = Δa/Δt

once you know m, you can use the equation above:
a = mt+b
use a = 311
use t = 2009
use m = the slope you calculated
solve for b

now you know m and b.

now you just write the equation:
a=mt+b
but put in the values for m and b that you figured out, and that is the answer to part A, the rest is easy.