Check the forward differences of the sequence.
If
, then let
be the sequence of first-order differences of
. That is, for n ≥ 1,

so that
.
Let
be the sequence of differences of
,

and we see that this is a constant sequence,
. In other words,
is an arithmetic sequence with common difference between terms of 2. That is,

and we can solve for
in terms of
:



and so on down to

We solve for
in the same way.

Then



and so on down to


Answer:
17. 13 miles : 1 hour
19. 12 saved : 1 week
21. $0.47 : 1 pound
23. $1.33 : 1 gallon
Step-by-step explanation:
Your goal is to make the second numbers, "1." So divide the first numbers by the second number to simplify.
Ex: 104 ÷ 8 = 13 Therefore, 13 miles per 1 hour (13 miles : 1 hour)
You'll see how to set up a table, choose appropriate x-values, plug those values into the equation.