收支平衡

\begin{aligned} \text{盈亏平衡点（数量）} &= \frac{FC}{P_i - VC_i} \\ \\ \text{盈亏平衡收入} &= \text{盈亏平衡点（数量）} \times P_i \\ \\ \text{边际贡献率} &= \frac{P_i - VC_i}{P_i} \end{aligned}