Answer:
x=74.5
Step-by-step explanation:
31+2x=180
Every inside of a triangle is 180 degrees
The next step is to subtract 31 from both sides to get
2x=149
divide both sides by two to isolate the variable to get
x=74.5
Hope this helps. If you have any follow-up questions, feel free to ask.
Have a great day! :)
