Question

1. What is the 19th term of the arithmetic sequence 15, 23, 31, ...?

2. What is the 25th term of the arithmetic series 9, 15, 21, ...?

Answer 1

do you know the formula?

Answer 2

no sorry

Answer 3

we start with 15. then for each subsequent term we add 8. so, for the 2nd term we add one 8 and for the third term we add two 8's to the starting point 15. so for the 19th term we will add 18 8's or 18*8=144 to 15 or 159. now can you do #2?

Answer 4

\[\LARGE a_n=a_1+(n-1)d\]
a_ is the first term and d is difference
we have:
\[\LARGE d=a_n-a_{n-1}\]
\[\LARGE d=a_2-a_1\]
\[\LARGE d=23-15\]
\[\LARGE d=8\]
now we substitute:
\[\LARGE a_{19}=15+(19-1)8\]
go on...

Answer 5

for number one i got 159 and number 2 i got 153

Answer 6

those are correct