What is the length of side AD?

Astudent simplified a rational expression as shown.

For f(x)=2x+3 and g(x)=x^2- 8 find (f+g) (x)

At the beginning of year 1, carlos invests $600 at an annual compound interest rate of 4%. he makes no deposits to or withdrawals from the account. which explicit formula can be used to find the account's balance at the beginning of year 5? what is, the balance?