Please help and also include an explanation so I know how you got the answer.

Answer:
x = 15
Step-by-step explanation:
We know that 4x° + 8x° make a straight angle of 180°.
4x° + 8x° = 180°
12x° = 180°
12x = 180
x = 180/12 = 15
Answer:
x=15
Step-by-step explanation:
I gotcha bro
The line C is straight and straight lines are 180°
so 180° = 4x + 8x = 12x ----> 180 = 12x ---> then divide both sides by 12
180/12 = 15 and 12x/12 = x
so 15 = x or x = 15