Which has a value closest to 9?

Iam so stuck. what is the worked out answer for this question?

Abox of chocolates costs $7. which equation relates the number of boxes sold (x) and total cost of the boxes sold (y)?

Each month, a shopkeeper spends 5x + 14 dollars on rent and electricity. if he spends 3x−5 dollars on rent, how much does he spend on electricity? for which value(s) of x is the amount the shopkeeper spends on electricity less than $100? explain how you found the value(s).