Question

What is the 25th term of the arithmetic series 9, 15, 21, ...? (3 points)

151
152
153
154

Answer 1

do u know the n'th term formula for arithmetic series?

Answer 2

I know the formula i just always have a hard time plugging numbers in

Answer 3

ok, 1st term a1 = 9
common difference d=15-9 = 6
n=25.
plug them in and tell me what u get ?

Answer 4

but you already put what they equal??

Answer 5

an = a+(n-1)d
so,
a25 = 9+(25-1)6
can u find a25 ?>

Answer 6

33*6 then?

Answer 7

but that isn't one of the answers
I am doing something wrong

Answer 8

9+24*6=...?

Answer 9

you multiplt 24 by 6 first then add 9

Answer 10

first you multiply.

Answer 11

oh right.
PEMDAS

Answer 12

153

Answer 13

very good!

Answer 14

yes.