Q. Static single variable model and static multivariable model?

Static single variable model: Methods using this model utilize an equation to estimate the desired value such as time, cost and effort and so on they all depend on same variable used as predictor (say, size). An illustration of the most common equation is C= a Lb

Where C is the cost effort expressed in the unit of manpower for example persons months and L is the size generally given in the line of code (LOC). The constants a as well as b are derived from the historical data of the organization. Since a as well as b depends on the local development environment these models are not transportable to different organizations.