Two supplementary angles have the following measures: m A B C = 135° and m CBD = 9x°. What is the equation to solve for x?

Question

A. 9x° - 135° = 180°
B. 9x° + 135° = 90°
C. 9x° + 135° = 180°
D. 9x° = 180°

Answer 1

Since the angles are supplementary, the sum of their measures must be 180°. Therefore, the equation to solve for x is 9x° + 135° = 180°.