How do I solve this? Can someone please help me

Answer:
finding the area of the triangle of the exterior angle
Step-by-step explanation:
2x° (3×-12) (4×+9)
36° 36°
2x +36° + 36° = 108°
2x
___+36°__
72
72
__+36°__
108°
so the answer is 108°
hoped i helped