Answer:
X = 12
Step-by-step explanation:
This is quite simple!
Those two angles MUST add up to 180° since it is a straight angle.
Therefore, you can set them equal to 180°
54° + 10x + 6° = 180°
60° + 10x = 180°
-60° -60°
10x = 120°
10x/10 = 120/10
X = 12
Hope this helps! :)
