Which of the following describes the correct process for solving the equation 3X +6 equals 21 and arrives at the correct solution A. divide both sides by six and then add three. The solution is X = 5 B. add six to both sides of the equation and then divide by three. The solution is X equals 9 C. subtract six from both sides of the equation and then divided by three. The solution is X equals eight D. subtract six from both sides of the equation and then divide by three the solution is X= 5