Answer:
[tex] x = 6 \\ \\ m<NBS = 68[/tex]
Step-by-step explanation:
m<NBS+ m<SBR = m<NBR
[tex](12x - 4) + 42 = 17x + 8 \\ \\ 12x + 38 = 17x + 8 \\ \\ 17x - 12x = 38 - 8 \\ 5x = 30 \\ \\ x = \frac{30}{5} \\ \\ x = 6[/tex]
[tex]m<NBS = 12x - 4 \\ = 12(6) - 4 \\ = 72 - 4 \\ = 68[/tex]
I hope I helped you^_^
