Which equation represents a proportional relationship?

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 of the following is true for the relation f(x)=2x^2+1

The measures of the legs of a right triangle are 15m and 20m . what is the length of the hypotenuse