Look at this picture and answer plz i already got the first part i just need the rest also tell me if the first part is correct Or not

Just tell me how to set up the equation.

What value of x is in the solution set of 4x – 12 s 16 + 8x?

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?