Question

I have no clue what to do? The first four terms of a sequence are shown below:

7, 4, 1, -2

Which of the following functions best defines this sequence?

Answer 1

This is an arithmetic sequence because every term is 3 less than the one before it. The formula for any term of an arithmetic sequence is
\[a_n=a_1+d(n-1)\]
a1 is the first term (7) and d is -3 because the pattern is subtracting 3

Answer 2

Plug in for a1 and d, then simplify

Answer 3

but were did you get -3 from? and what about 4, 1 , and -2

Answer 4

4-3=1, 1-3=-2