When you divide 7.7 by 700 how many decimal places will the quotient have?

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?

Hey hotel charges guests $19.75 a day to rent five video games at this rate which expression can be used to determine the charge for renting nine video games for one day at this hotel? pls

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /