Answer:
A. 5x° + (2x + 7)° = 90°
Step-by-step explanation:
Complementary angles add up to give us 90°.
From the given diagram, we have a part of the angles on a straight line as a right angle. Which means it is 90°. Therefore, the other two angles, 5x° and (2x + 7)° will add up to give us 90°. Thus, 5x° and (2x + 7)° are complementary angles.
Therefore:
5x° + (2x + 7)° = 90°