Answer:
Jon's car can travel an average of 35 miles per gallon.
It is given that gallon = g.
How much gallons does he need to travel 656 miles. Set the equation.
656 = 35g is your equation.
Isolate the variable, g. Note the equal sign, what you do to one side, you do to the other. Divide 35 from both sides:
(656)/35 = (35g)/35
g = 656/35
g = ~18.75 gallons
Jon will need ~18.75 gallons to complete the trip.