Answer:
My guess is 21
Step-by-step explanation:
<B = 3(14) + 6 = 48 degrees
4x+6+3x+6+5x = 180 degrees
12x + 12 = 180
12x = 180 - 12
x = 168/12
x = 14
tbh idk know the answer
bc i didnt do it