Polynomial Equation

[Paul75]

Hi.
I have a table of x and y values that I have graphed and added a polynomial trend line and included the formula on the chart. How do I use this formula to now input an x value (temperature, say 0 degrees) and come up with the corresponding y value (length).

I'm an excel beginner so any help is much appreciated.

Regards,
Paul.

[MrShorty]

Two ways:

1) Hand enter the coefficients from the chart trend line into the spreadsheet, then you can build a simple worksheet function to do the calculation.

2) Use the LINEST function to generate the coefficients directly in the spreadsheet, then use those coefficients to build a function to calculate y at a given x.