What is 50 + 100 - 150 x 2

Icould really use some with this question.

Which of the following is the explicit rule for a geometric sequence defined a recursive formula of a -5a for which the first term is 23?

Eliza wants to make $10,000 from her investments. she finds an investment account that earns 4.5% interest. she decides to deposit $2,500 into an account. how much money will be in her account after 14 years?