I imagine you could tweak Solver's parameters and/or scale your own
values to get Solver to work, but, in this specific instance, you
should consider using LINEST as Bernard suggested.

If you did, you would discover that none of the coefficients for an
order 3 fit are statistically significant at the 5% level. Only the
constant term is significant for a quadratic fit whereas both terms are
for a linear fit. To learn more about how to test for statistical
significance check the LINEST help Example 5.

--
Regards,

Tushar Mehta
www.tushar-mehta.com
Excel, PowerPoint, and VBA add-ins, tutorials
Custom MS Office productivity solutions

In article ,
says...
I tried to create equations from the set of data by solver
x= 90021 85248 78314 69768 59508 47975
y = 20.09 19.92 18.70 16.95 16.13 15.67

in the form of y= a + bx +cx2 + dx3;
where x2= x square ,x3 = x cube.

but could not do so.
the solver does fine when the value of x is small .
Your help will be hghly appreciated in this regard.

Thanks