Please help me with this math problem!! :) I will mark brainliest!! :)

Answer:
x = 36
Step-by-step explanation:
180 - 48 = 132
This is because angle AC- and ACB form a straight angle (180 degrees).
132 + 12 = 144
180 - 144 = 36
The three interior sides of a triangle always add up to 180 degrees.
Hope this helps!