What do you notice about each solution? what do you notice about the graphs for

Triangle PQR is similar to triangle LMN, so their angles are the same. That is, ∠M = ∠Q = 55°. Since the total of angles is 180°, x can be found from ...
  x° +39° +55° = 180°
  x = 180 -39 -55
  x = 86


x can also be found as the difference
  x° = arctan(slope(LM)) -arctan(slope(LN)) = arctan(3) -arctan(-1/4)
  x ≈ 86.