Question

Find the 11th term of the arithmetic sequence.

a3= 20.5 and a8= 13,a11=

Answer 1

an = a1 + (n-1)d
use a3 and a8 to find a1 and d then find a11

Answer 2

so which is n

Answer 3

a3 here n=3

Answer 4

a8 here n=8 and a11 here n=11

Answer 5

so then those are the answers

Answer 6

no

Answer 7

cuz when i put the 3 in i just got 3

Answer 8

a3=a1+(3-1)d
20.5 = a1 + 2d ....i

a8 = a1 + (8-1)d
13 = a1 + 7d ....ii

Answer 9

can u solve equation i and ii to find a1 and d?

Answer 10

no they didnt explain that

Answer 11

subtract equation ii from i and we get,
20.5 -13 =a1 +2d -a1 -7d
7.5 = -5d
d= -7.5/5
d=-1.5
Now, when d= -1.5 then from equation i , 20.5 = a1 + 2*(-1.5)
a1=23.5

Now,
a11 = a1 + 10d = 23.5 + 10*(-1.5) =8.5

Answer 12

got it???

Answer 13

sry no

Answer 14

do u know that nth term of a arithemetic sequence is an = a1 + (n-1)d

Answer 15

i know that but they never said anything about i

Answer 16

well, you should know it before trying to solve these kind of problems

Answer 17

thier no other way to solve but this way

Answer 18

yes there are but all uses the idea an=a1+(n-1)d

Answer 19

i noe how to use the formula but what confushes me is the I

Answer 20

???

Answer 21

nvr so i went back to what ur talking about is 9.27?

Answer 22

no

Answer 23

what the the problem