Question

Thanks!

Answer 1

on the first problem..your asking how many terms..so you're looking for n in

An = A1 + (n-1)d

so An = 2 since it's the last term
A1 = 178 coz it's the first term
d = A2 - A1 = 170 - 178 = -8

substitute..then tell me what you got

Answer 2

you know the 1st and last term

common difference is - 8

a= 178

Use

\[T _{n}: 2 = 178 + ( n-1) (-8)\]

Expand and simplify then solve for n

2 = 178 - 8n + 8

8n = 184

n = 26

there are 26 terms in the series

Answer 3

tn=ar^n-1

Answer 4

a=first term
r=ratio
tn=last term

Answer 5

Thanks guys your awesome!

Answer 6

for the 2nd question a = -9, d= 4 and n = 12

Use \[s _{n} = n/2(2a + (n - 1)d)\]