Factor completely please

Ineed to learn how to solve this problem

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.

At your job you're paid $50 per week plus $3 per sale at least how many saled do you need to make in order to have over $250