Question

Please Help Me...

Find The a9 to each sequence.

an=-2(-5)n-1

an=6(-3)n-1

an=-7 n-1

These are Geometeic Sequences and It's asking for the a9, which I believe is the 9th term for all of them step by step.​

Answer 1

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

:substitutute 9 in place of "n" in the equation

= -2(-5)9-1

Multiply -2 and -5 to get positive 10

=(10)(9)-1

Multiply 10 and 9 to get 90

=90-1

Subtract 1 from 90

=89 therefore 9th term is 89

Explanation:

For

an= 6(-3)n-1

(Follow the above procedure)

=6(-3)9-1

=-18-1

=-19

For

an= -7n-1

(Follow the same procedure as above)

-7(9)-1

=-63-1

=- 64