Answer:
The first option.
Because we're solving for the price of each gallon, x will represent the cost of each gallon. Since 8.4 is the total amount of gallons, multiply 8.4 and x to get $23.94. Solve for x by dividing 23.94 to get $2.85 per gallon. To check this, substitute 2.85 for x into the equation: 8.4 (2.85) = 23.94
