Find the first, fourth, and eighth term of the sequence:A (n) = - 2•5n-1

An=a1 (r) ^ (n-1)

a1=first term

r=common ratio

n=which term

so

an=-2 (5) ^ (n-1)

first term is - 2

4th term is subsitue 4 for n

a4=-2 (5) ^ (4-1)

a4=-2 (5) ^3

a4=-2 (125)

a4=-250

4th term is - 250

8th term

a8=-2 (5) ^ (8-1)

a8=-2 (5) ^7

a8=-2 (78125)

a8=-156250

8th term is - 156250

A (1) = - 2 x 5 (1) - 1 = - 11

A (4) = - 2 x 5 (4) - 1 = - 41

A (8) = - 2 x 5 (8) - 1 = - 81