The first four terms of a sequence are shown below:

8, 5, 2, -1

Which of the following functions best defines this sequence?

f(1) = 8, f(n + 1) = f(n) + 3; for n ≥ 1

f(1) = 8, f(n + 1) = f(n) - 5; for n ≥ 1

f(1) = 8, f(n + 1) = f(n) + 5; for n ≥ 1

f(1) = 8, f(n + 1) = f(n) - 3; for n ≥ 1

Question

The first four terms of a sequence are shown below:

8, 5, 2, -1

Which of the following functions best defines this sequence?

 f(1) = 8, f(n + 1) = f(n) + 3; for n ≥ 1

 f(1) = 8, f(n + 1) = f(n) - 5; for n ≥ 1

 f(1) = 8, f(n + 1) = f(n) + 5; for n ≥ 1

 f(1) = 8, f(n + 1) = f(n) - 3; for n ≥ 1

solomonzelman · Answer

$\large\color{darkviolet}{ d=a_{n}-a_{n-1}  }$

solomonzelman · Answer

$\large\color{darkviolet}{ d=5-8=-3  }$

solomonzelman · Answer

So each next term is going to be 3 less than the one before it.
n≥1 is in all cases, because you need to have positive terms, and not anything like -1st term....

solomonzelman · Answer

Which option do you pick ?

anonymous · Answer

I assumed it was c I just wanted to be sure before I submitted my test.

solomonzelman · Answer

it is not C

anonymous · Answer

B?

anonymous · Answer

@SolomonZelman

solomonzelman · Answer

you are obviously trying to guess the answer.

anonymous · Answer

Thanks dude