write a rule for the -nth term of the arithmetic sequence. then find the 12th term.

1)24,35,46 ....

2) 31,17,3 ......

Question

write a rule for the -nth term of the arithmetic sequence. then find the 12th term. 

1)24,35,46 ....

2) 31,17,3 ......

anonymous · Answer

@jim_thompson5910 can you explain this to me please

jim_thompson5910 · Answer

24,35,46

what's the first term of the sequence above

anonymous · Answer

like the first number?...24 ?

jim_thompson5910 · Answer

yep good

jim_thompson5910 · Answer

what is the common ratio of 24,35,46, ...

anonymous · Answer

keep adding 11

jim_thompson5910 · Answer

good

jim_thompson5910 · Answer

first term: a1 = 24 
common ratio: d = 11

jim_thompson5910 · Answer

now plug these two things into the formula below

a_n = a1 + d(n-1)

and simplify

anonymous · Answer

what do they mean by 12th term? how?

jim_thompson5910 · Answer

what did you get for the nth term

anonymous · Answer

for the n1 ...do I just leave it like that?

anonymous · Answer

im at an=24+11(n1)

jim_thompson5910 · Answer

a_n = a1 + d(n-1)

a_n = 24 + 11(n-1)

a_n = 24 + 11n-11 ... distribute

now combine like terms

anonymous · Answer

do i add 11?

anonymous · Answer

or just make it the n stand alone

jim_thompson5910 · Answer

24 - 11 = ??

anonymous · Answer

13

jim_thompson5910 · Answer

so the nth term is 

a_n = 11n + 13

jim_thompson5910 · Answer

to find the 12th term, plug in n = 12 and evaluate/simplify

anonymous · Answer

to where?

jim_thompson5910 · Answer

a_n = 11n + 13

a12 = 11*12 + 13 ...plug in n = 12

a12 = ??

anonymous · Answer

145

jim_thompson5910 · Answer

good

jim_thompson5910 · Answer

that's the 12th term of 24,35,46, ...

anonymous · Answer

the next one ... would i use the same formula ? an=a1+d(n-1)

jim_thompson5910 · Answer

correct since that's also an arithmetic sequence

anonymous · Answer

and for example on the next question it says find the tenth term of the arithmentic sequence in which a1=-8 and d=-2 ....how would i find that?

jim_thompson5910 · Answer

first find the nth term, then plug in n = 10 to find the tenth term

anonymous · Answer

ok got it ! how would i answer the question .  a theater has 13 seats in the first row. each row after the first has 4 more seats than the previous row. write a rule for the -nth term of this situation ?

jim_thompson5910 · Answer

hint: 

first term: 13
common difference: 4

anonymous · Answer

how many seats are in the 11th row?

anonymous · Answer

how would i find that

jim_thompson5910 · Answer

plug in n = 11 and evaluate

anonymous · Answer

plug it in to what number

jim_thompson5910 · Answer

to what you got for your nth term

jim_thompson5910 · Answer

what's your nth term

anonymous · Answer

i got an=4n+12

anonymous · Answer

would it be 56?

jim_thompson5910 · Answer

nth term

an = 4n + 9

plug in n = 11 to get the 11th term

a11 = 4*11+9 = 53