Постепенно раскрываем скобки
4т-(3n+(7m-(8n-(3+2m=4т-(3n+(7m-(8n-3-2m)))=4т-(3n+(7m-8n+3+2m)=4т-(3n+7m-8n+3+2m)=4т-3n+7m-8n+3+2m=4т-11n+9m+3
Постепенно раскрываем скобки
4т-(3n+(7m-(8n-(3+2m=4т-(3n+(7m-(8n-3-2m)))=4т-(3n+(7m-8n+3+2m)=4т-(3n+7m-8n+3+2m)=4т-3n+7m-8n+3+2m=4т-11n+9m+3