What is the 17th term of the arithmetic sequence 18, 22, 26, ...?

Question

amistre64 · Answer

the beneral set up of any arith seq is such that:

an = a1 + d(n-1)

find the common "d" (difference) and the first term (a1) and you can determine any other term.

anonymous · Answer

ok so A1 = 18

anonymous · Answer

because it is the first

amistre64 · Answer

correct; a1 = 18

amistre64 · Answer

what do we have to add to get from a1 to a2?

18 + d = 22

anonymous · Answer

4

amistre64 · Answer

good, then lets put those into the general set up and see where it takes us

an = a1 + d(n-1)

an = 18 + 4(n-1)

we want the nth term to be the 17th term right?  n = 17

so whats a17 turn out to be?

anonymous · Answer

os so I plugged in 18+4(17-1) and got 22(16) = 352

anonymous · Answer

But I got it wrong didn't I

amistre64 · Answer

the set up is good, lets just dbl chk the mathing :)

a17 = 18 + 4(16)
       = 18 + 64
       = 82

amistre64 · Answer

order of operations is important

remember to mulitply or divide first ...

anonymous · Answer

oh so we plug it into the an ok but how did the 16 come about ... ok

amistre64 · Answer

n-1 is what the general formula states; 17-1 = 16

the nth term in this case is the 17th term

anonymous · Answer

ok thanks

amistre64 · Answer

youre welcome