Angle BCD is a circumscribed angle of circle A. What is the length of line segment AC?

The graph shown is the graph of which function?

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?

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