Idon't understand how to put anything into standard form. if anyone could that'd be great.

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.

Can someone me with these two circle theorem questions asap?

Julie was able to walk 16 km through the zoo in 6 hours. how long will it take her to walk 24 km through the zoo?