An equation for the sentence would be g + 7 = 12, where g is the unknown number of gallons.
Answer:
x = 12
Step-by-step explanation:
The diagram shows an equilateral triangle (because all angles are congruent). All sides in equilateral triangle are congruent, so

Solve the equation

Check this value:

Thus, 
You may park 20 feet from a crosswalk.