I need help with 1-3 and 5-6 pls

(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