The answer is A, or 10.
Explanation:
These two angles are supplementary, meaning that they add up to 180 degrees. Upon plugging 10 in as x, you would get 67 as the answer for the left angle measurement and 113 as the answer for the right angle measurement. Because 67 + 113 = 180, you know that the math you did is correct. Linear pair angles always are supplementary, and they are directly beside each other horizontally or vertically.
