Need with arithmetic and geometric sequence setting up

First term a=2, common difference d=3, formula

98

First five terms, first term 5, common ratio 2. Write down 5, keep multiplying by two until you've written down five terms.

5 10 20 40 80

Savings plan. Anybody see the flaw in this plan?

First term 1, common ratio 5.

$78,125

whats the