Ireally have no idea how to do this

Question 14 (1 point) larry deposits $15 a week into a savings account. his balance in his savings account grows by a constant percent rate.

Solve the equation for b: a= (1/2)(b)(h)

Calculate the total payback for a $3,500 loan at 8% annual interest with monthly payments for two years. show all of your steps. use the formula, m = pm(1 + m)^na/(1 + m)^na - 1, as needed.