Identify a, h, and k for the equation

4+6x-3x^3 in standard form with explanations because i don’t understand

A) if $50000 is invested in a bank account that pays 9.3% of interest compounded on a six-monthly basis, how much money will be in the account after 3 and 12 years? b) if matusalen's father had put $2.0 in the bank when he was born and there, how long would matusalen have had to his death (969 years later) if the interest was 7% per year composed each month and weekly?

If the sales price of a dvd is $20 and the markup is 34%, what is the cost of the dvd?