Answer:
[tex]=-10n-3[/tex]
Step-by-step explanation:
[tex](-n3 - 8n - 6) + (-8n+ 9n + 3)\\\mathrm{Remove\:parentheses}:\quad \left(-a\right)=-a\\=-n\cdot \:3-8n-6-8n+9n+3\\Group\:like\:terms\\=-3n-8n-8n+9n-6+3\\\mathrm{Add\:similar\:elements:}\:-3n-8n-8n+9n=-10n\\=-10n-6+3\\\mathrm{Add/Subtract\:the\:numbers:}\:-6+3=-3\\=-10n-3[/tex]
