Charles's law is sometimes expressed in the form V = Vo (l + a), where is the

Charles's law is sometimes expressed in the form V = Vo (l + aθ), where θ is the Celsius temperature, a is a constant, and Vo is the volume of the sample at O°e. The following values for a have been reported for nitrogen at O°C:
P/Torr 749.7 599.6 333.1 98.6
103a/ (oC)-1 3.6717 3.6697 3.6665 3.6643
For these data calculate the best value for the absolute zero of temperature on the Celsius scale.