Answer:
Since the two angles are across from each other that tells us that they are equal in length, so we want to set them equal to each other
3x+50=6x-10, Now we want to solve it like a normal equation, get x by itself
First add 10 to each side
3x+50+10=6x-10+10
3x+60=6x
Now we want to subtract 3x from each side
3x-3x+60=6x-3x
60=3x
Now divide both sides by 3
60/3=3x/3
20=x
x=20
Hope this helps ;)
Explanation: