Help with a and describe

For the sequence [tex]a_{n} = 2n/(n+1)[/tex], what is the value of [tex]a_{10}[/tex]

What is the equation of the line graphed?

Which account has the highest effective annual interest rate? not necessary but show how you got your answer. a. account 1: interest is compounded quarterly at an annual rate of 4.20%.b. account 2: interest is compounded monthly at an annual rate of 4.15%.c. account 3: interest is compounded semiannually at an annual rate of 4.10%d. account 4: interest is compounded annually at a rate of 4.25%.