What are all the exact solutions of sqrt 2 cosx-1=0 for 0 less than or equal to x less than or equal to 2

Jada has a meal in a restaurant she adds up the prices listed on the menu for everything they ordered and gets a subtotal of $42.00. when the check comes, it says they also need to pay $3.99 in sales tax. what percentage of the subtotal is the sales tax