Direct materials are items listed in a bill of materials, like raw materials and transportation costs. Indirect materials are consumed but not listed in the bill of materials, like tools, machinery, and equipment. Fixed expenses like depreciation are constant in the short-term, but all expenses are variable in the long-term. The equation for output is Y=mx+c, where mx are variable expenses and c are fixed expenses. Every company has a vision, mission, code of conduct, and core values. Key stakeholders include employees, suppliers, customers, shareholders, and society. Good companies focus on achieving economic, societal, and environmental profits in their triple bottom line.