From what it looks like 7x and 11x are being used as units of measurment. I can asssume a full circle adds up to 36x because 180deg adds up to 18deg.
If there were a number that was supposed to fill in for x it could be 0 because if the angles in this problem were 110 deg and 70 deg they would make 180 deg which is the straight line that the problem has.