Since the angles are opposite angles they are equal. This means the equation to solve this would be:
9x + 15 =55
The Subtraction Property of Equality states that we can subtract the same amount from both sides of the equation and have an equivalent equation afterwards.
So subtract 15 from both sides to get:
9x = 40
The Division Property of Equality states that we can divide the equation on both sides of the equation and have an equivalent equation afterwards.
