It’s a i not a 1 (13+i)^2

Need help please ??

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 number if marbles of different colors stored in a hat is listed below: 4 red marbles 10 green marbles 7 blue marbles. without looking in the hat, dan takes out a marble at random. he replaces the marble and then takes out another marble from the hat. what is the probability that dan takes out a blue marble in both draws?

The function v(r)=4/3pir^3 can be used to find the volume of air inside a basketball given its radius. what does v(r) represent