Answer:
x= 20
Explanation:
The two angles form a straight line so they add to 180 degrees
The first angle is 3x+40 and the second angle is 80. The add together to form a straight line. The straight line is 180 degrees.
3x+40 + 80 = 180
Combine like terms
3x+120 = 180
Subtract 120 from each side
3x+120-120=180-120
3x = 60
Divide each side by 3
3x/3 = 60/3
x = 20