Question

Em um triangulo ABC,a medida do angulo BAC excede a medida de ABC em 10°,e a medida do amgulo ACB,adicionada de 30°,é igual ao dobro da medida de BAC.Quais são as medidas dos angulos deste triangulo?

Answer 1

the question in English is

In a triangle ABC, the measure of the BAC angle exceeds the ABC measure by 10 °, and the measure of the ACB angle, added by 30 °, is equal to twice the BAC measure. What are the measures of the angles of this triangle?

Let 
A=m ∠BAC
B=m∠ABC
C=m∠ACB

we know that
A+B+C=180-----> equation 1
A=B+10-----> B=A-10------> equation 2
C+30=2A----> C=2A-30----> equation 3

substitute equation 2 and equation 3 in equation 1
A+[A-10]+2A-30]=180------> 4A=180+40-----> A=220/4-----> A=55°
B=A-10----> B=55-10-----> B=45°
C=2A-30-----> C=2*55-30----> C=80°

the answer is
m ∠BAC is 55°
m∠ABC is 45°
m∠ACB is 80°

the answer in Portuguese

Deixei
A=m ∠BAC
B=m∠ABC
C=m∠ACB

nós sabemos isso
A+B+C=180-----> equação 1
A=B+10-----> B=A-10------> equação 2
C+30=2A----> C=2A-30----> equação 3

substitute equação 2 e equação 3 dentro equação 1
A+[A-10]+2A-30]=180------> 4A=180+40-----> A=220/4-----> A=55°
B=A-10----> B=55-10-----> B=45°
C=2A-30-----> C=2*55-30----> C=80°

a resposta é
m ∠BAC is 55°
m∠ABC is 45°
m∠ACB is 80°