Respuesta :

Answer:

x = 21°

Step-by-step explanation:

Vertical angles have the same measures, therefore:

3x - 30 = 2x - 9

x - 30 = -9

x = 21°

Answer:

21

Step-by-step explanation:

If mZA=mB

3x-30°=2x-9

TRANSPOSE

3x-2x=-9+30

1x=21

X=21