Because of the Vertical Angle Theorem, you know both angles are congruent. Therefore, 1/4x+3=3/4x-7. Solving for x, x=20, and the angle measure is 8 degrees.
They're equivalent to each other so write it out so they equal each other. Then subtract 3 from both sides and u get 1/4x = 3/4x - 10. After that you subtract 3/4 from both sides and u get -2/4x = -10. Now u divide both sides by -2/4 (or -1/2). and get x =20.
