Find the value of x.
A.18
B.15
C.16
D.19
PLEASE HELP!!!!!

Answer:
x = 19
Step-by-step explanation:
123°+3x = 180°
3x = 180°-123°
3x = 57
x = 57/3
x = 19
The reason why we use 123° + 3x = 180° because both are adjacent angles. Adjacent angles add up to 180°