Hello! Please help I will rate five stars and say thank you

Answer: (C) 7x + 11x =90
Step-by-step explanation: The angle is a right angle which means that it equals 90 degrees so both angles in the right angle will add up to 90 degrees.
Answer: A is your answer.
Step-by-step explanation: If you look at the possible answers then you will see that A\B. is not possible as 7x + 11x = 90 because those are the two it that right angle.