Answer: B
Step-by-step explanation:
By the Exterior Angle Theorem, we know that the exterior angle is equal to the sum of the two opposite interior angles.
(2x+8)+(3x+5)=123 [combine like terms]
5x+13=123 [subtract both sides by 13]
5x=110 [divide both sides by 5]
x=22
Now, we know that the answer is B.
