The two angles are the same value. To find, think of the equation 3x+50=6x-10. Put the 6x to the other side of the equation. You shall get -3x+50=-10. Move the 50 to the other side, and you'll end up with -3x=-60. Divide each number by -3 to find x now. Your final answer will be x=20.
Answer: x=20