Need to editing.
theory and so the model should be changed, then the Excel estimation should be changed accordingly; i.e. you need to re-run the model with 2 Variables in the right side, X & X2(squared).
ay2 = 1+ bx2
It should be
Y = a +bX +CX2(X*X).
Your theory and so the model should be changed, then the Excel estimation should be changed accordingly; i.e. you need to re-run the model with 2 Variables in the right side, X & X2(squared).