i found this now that you pointed me to SERIESSUM

How to use the SERIESUM() function:

Type "=SERIESSUM(".
Enter the coordinate of the "x" value "1"
Type a comma.
Enter the coordinate of the "n" value "1".
Tyep a comma.
Enter the coordinate for the "m" value "1".
Type a comma.
Enter the coordinates for the range of "coefficients", "C2:C4".
Type ")" then press the "Enter" key

this is my data
10000 50
50000 200
200000 1800
350000 3500

and this is the formula from a 3rd order poly
y = -1E-13x3 + 6E-08x2 + 0.0003x + 40.755

Does the above mean that I have to type the coords manually? I was hoping that the formula could be inserted such that if the data was tweaked this would be updated behind the scenes.