The product of numbers on the diagonal when comparing two ratios

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.

Which expression do you get when you eliminate the negative exponents of 4a^2 b^216a^-3 b

Kayaks rent for $35 per day. which expression can you use to find the cost in dollars of renting 3 kayaks for a day?