Find the value of the underlined digit 814295 the digit is 8

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 out here and the tell me the greatest common factor

Determine which expressions represent real numbers and which expressions represent complex number. asaaap! plis!