Geometry

Question Analysis

This question involves the property of adjacent angles on a straight - line.

 

Key Concept Explanation

Adjacent angles formed on a straight line are supplementary, meaning their sum is .

 

Step - by - Step Solution

1. Notice that the angle and the angle are adjacent angles on a straight line.

Based on the supplementary angle property, we can set up the equation .

2. Simplify the left - hand side of the equation:

Combine like terms: