Does 1 to 3 solve a portion

Steve wants to develop a way to find the total cost of any item including sales tax. the sales tax in his city is 6%. his friend jenna writes the expression x + 6x where x is the cost of the item. explain whether her expression is correct based on the situation.

Average acceleration: i have no idea how to do this.

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)