According to the picture, you can assume that angle X is congruent to angle Y due to their triangle shape. Here is the work:
1. Set the equations equal to one another: 4x-8 = 2x
2. Move the variables to get the "x" values on one side: 2x = 8
3. Divide by 2 to get "x": x = 4
4. Plug in "x" into the Angle X equation: 4(4)-8 = angle x....16-8....8
Angle X is 8 degrees. Hope this helped :)