Please help me with all 3, I will mark brainliest as long as u tell me how u got those answers

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.

Alex's monthly take home pay is $2,500. what is the maximum bad debt payment he can maintain without being in credit overload?

Answer this question i need as soon as possible