Factor 40x^3-5y^3 COMPLETELY

Simply 8x squared + 5(7x squared- x) - 2x =

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 check if i did this right since i really want to make sure it’s correct. if you do you so much