If a person uses $700 in credit with an interest of 14%,what is that person going to owe after three billing cycles with simple interest

Simple interest:  i = p*r*t, where r is the annual interest rate and t is the number of years.
                                14%
This boils down to interest per month:  a monthly rate of 0.0117.
                                12 mo

Thus, after 3 months, the amount owed, including the original $700, would be $700 + 3($700)(0.0117) = $724.57.