What is the domain of the graph

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.

If the scale factor between two circles is 2x/5y what is the ratio of their areas?

The difference between two numbers is one. three times the larger number minus two times the smaller number is 9. what are the two numbers