Incorrect. By adding the first and second equations of the system, you eliminate the variable f. This gives you the new equation. Then add the first and third equations to eliminate the variable f once again. This gives you a second new equation. Add these two new equations to eliminate the variable d. Then solve for e in the resulting equation. Substitute this value of e into one of the other new equations and solve for d. Finally, substitute the values for d and e into one of the original equations and solve for f. The correct answer is 3.