In ΔNOP, m ∠ N = ( 9 x + 8 ) ∘ m∠N=(9x+8) ∘ , m ∠ O = ( 4 x + 13 ) ∘ m∠O=(4x+13) ∘ , and m ∠ P = ( 2 x − 6 ) ∘ m∠P=(2x−6) ∘ . Find m ∠ N . m∠N.