Hi there! The answer is x = 20°
The angles are supplementary, which means that the sum of the angles is 180°.
The sum of the angles also equals
[tex]3x + 40 + 80[/tex]
Therefore, we get the following equation.
[tex]3x + 40 + 80 = 180[/tex]
Collect terms
[tex]3x + 120 = 180[/tex]
Subtract 120
[tex]3x = 60[/tex]
Divide by 3
[tex]x = 60 \div 3 = 20[/tex]
