Respuesta :

Assuming ∠6 and angle ∠8 are vertical angles, then 
m∠6 = m∠8 
m∠6 + m∠7 = m∠7 + m∠8 = 180 

2x + 15 + 3x = 180 
5x = 165 
x = 33 

m∠7 = 2(33)+15 = 81 
m∠8 = 3(33) = 99 

m∠6 = m∠8 = 99