If f(x) is a linear function, what is the value of n?

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.

The perimeter of a rectangle is 42 inches. if the width of the rectangle is 6 inches, what is the length

50 points~ ! i have to turn this in tomarrow