Final answer:
The supplement of an angle that measures 7x is 180 - 7x.Correct option is D.
Step-by-step explanation:
The supplement of an angle is the angle that, when added to the original angle, equals 180 degrees.
In this case, the original angle measures 7x. So, the supplement of this angle would be 180 - (7x).
Therefore, the correct answer is option D) 180 - 7x.