model equation

例句：

1. 1. The model equation describes the relationship between variables.
   该模型方程描述了变量之间的关系。
2. 2. The engineer used a model equation to solve the problem.
   工程师使用一个模型方程来解决这个问题。
3. 3. The model equation was used to predict future trends in the market.
   这个模型方程被用来预测市场的未来趋势。