- Answer:
 - add all the equation for example the first question in there would be like
 
 (note - an equation contains an is equal to sign [=] and if a problem does not have an is equal to sign then it becomes an expression)
 just add all of them making an equation like 
2n° + 55° + 49° = 180° (angle sum property) 
 
 2n° + 104 = 108° 
 2n° = 108° - 104 
 i.e., 2n° = 76° 
 n = 76/2 therefore, 
 n = 38