First, find the supplement of the angle that is 105 degrees.
105 + 75 = 180
Now, we can find complete the lower left triangle's angles.
39 + 75 + ? = 180
? = 66 degrees
The 66 degree angle of the lower left triangle and angle x are vertical angles. Vertical angles are congruent.
Therefore, the measure of angle x is 66 degrees.
Hope this helps!
