5) 19x - 6 = 8 + 9x +66°
(subtract 9x)
10x - 6 = 74°
(add 6)
10x = 80°
(divide by 10)
x = 8°
Then you put x into m< NMK
8 + 9(8°)
8 + 72°
m<NMK = 80°
6) because m<DER and m<REF are identical equations you can just divide m<DEF (96°) in half which is 48°
7) vertical pairs because they're right across from each other