Please help me answer this

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.

Sarah used her calculator to find sin 125 degrees. she wrote down sin sin125 degrees.57. how could sarah recognize that her answer is incorrect?

At a cost of 200, your club bought 175 frisbees to sell at the pep rally. you plan on selling them for $5 each. what is the domain of the function?