Hello,

I have the following data;

y x1 x2
12 1 10
23 2 20
34 3 30
45 4 40
56 5 50


And I would like to fit the following formula to this dataset; "x1^2 + x2 *
x1 = y"

Can anybody give me a pointer on how to do this, preferebly without having
to linearize the dataset first? The "algorithm" proposed should however be
able to fit any formula / model to the dataset, eg be general about this.

Kind regards, Darius Blaszijk