Question

Find the 8th term of the arithmetic sequence:
3, 8, 13, 18, ...
Find the 11th term of the arithmetic sequence:
-3, -5, -7, -9, ...

Answer 1

difference is 5
3 + 7*5 = 38

Answer 2

11th term
difference is -2
-3 +10(-2) = -23

Answer 3

d = -2

an = a1 + (n-1)(d)

a(11) = -3 + (10)(-2) = -23; yep

Answer 4

Find the indicated sum for the arithmetic series:
\[\sum_{k-1}^{15} (50-20k)\]

Answer 5

last one please

Answer 6

the sum from 1 to 15 eh .......

i can do it the long way but I think the short cut is:

(a1 + a15)(15)
-------------
2

ill have to dbl chk meself :)

Answer 7

the main answer is 2?

Answer 8

just hold on :)

Answer 9

ok thanks

Answer 10

im thinking if I did it right its gonna be -110; but let me check on that first

Answer 11

ok

Answer 12

i guess that wasnt the formula I was thinking it was :)

When I add all the values up I get -1650

Answer 13

ok ya thats right thanks :)

Answer 14

i had the right formula i just forgot to multiply in the 15 :)

same answer