Answer:
C: 3x + 80 + 2x = 180
Explanation:
A straight line is equal to 180 degrees total the find x, you would add the number within the line and make it equal to 180.
3x + 80 + 2x = 180
add like terms
5x + 80 = 180
subtract 80 from each side
5x = 100
divide each side by 5
x = 20