Ineed with math. what is value of x?

How do you use the elimination method for this question? explain, because i really want to understand!

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. after tax the total is 45.99. what percentage of the subtotal is the total?

Asequence is defined recursively using the formula f(n + 1) =f(n) - 5. which sequence could be