angle A and angle b are supplementary angle

Question

A is 10 less than 3 times Angle B Write the system of equations

 

I need help understanding system of equations. Please answer the problem, and if you have time show me how to do system of equations. Thank you in advanced for all the help you have provided.

Answer 1

"suppulmentary" meen 2 angels add up tu 180 deg

a=3b-10

a+b=180

(3b-10)+b=180

4b-10=180

4b=170

b=170/4=42.5 deg