From the information given, the subtotal on the bill was $x. A tax of 7% was applied on this amount. Recall, percentage is expresed in terms of 100. This means that the amount of tax charged is
7/100 * x = 0.07x
Amount of bill including tax = initial amount + tax
Amount of bill including tax = x + 0.07x = 1.07x
Chase decides to leave a tip of 15% on the entire bill (including the tax). This means that the amount paid as tip is
15/100 * 1.07x = 0.1605x
Total amount paid = amount of bill including tax + amount of tip
Total amount paid = 1.07x + 0.1605x = 1.2305x
The expression for the total amount paid in terms of x is 1.2305x
