the closed form of the sequence an: 2,7,12,17,... is ___.
A. an=5n-3
B. an=2^n
C. an=n+1
D. an=10n-8

Question

the closed form of the sequence an: 2,7,12,17,... is ___.
A. an=5n-3
B. an=2^n
C. an=n+1
D. an=10n-8

anonymous · Answer

2,7,12,17,...

This is an Arithmetic Sequence.

The common difference is: +5

anonymous · Answer

2 + (5) = 7 
7 + (5) = 12 
12 + (5) = 17
17 + (5) = 22 
and so on...

anonymous · Answer

I saw that but I plugged in some of the values into the equations but none of them worked... so I don't know if i'm doing it wrong or not

anonymous · Answer

try again

anonymous · Answer

$$a _{n} = a _{1} + (n-1)d$$
a1 is the first term. 
d is the common difference.
$$a _{n} = 2 + (n-1)5$$
$$a _{n} = 2 + 5n - 5$$

anonymous · Answer

$a_1=2=5\times 1-3$

anonymous · Answer

Can you finish it up from there @paigeRG

anonymous · Answer

and $a_2=7=5\times 2-3$

anonymous · Answer

oooooooooooooohhhhhhhhhh I get it now I was subtracting first instead of multiplying first thanks guys!!!

anonymous · Answer

yw :)