As part of a prize, shaina received a certain number of gallons of gas at a gas station for free. after that, she paid the regular price per gallon of gas. the total number of gallons she used to fill her tank is unknown. the expression 4(g – 10) represents the amount shaina paid to fill her tank. what does the first factor in the expression represent? explain how you know. what does the variable g in the second factor represent? explain how you know. what does the number 10 in the second factor represent? explain how you know.