I have columns of known y's and a column of known x's whose relationship
follows a power series regression. I found Excel's FORECAST, and GROWTH
functions that will return a y for a given x using a linear regression and a
exponential regression, respectively. Is there such a way to extract a value
using a power regression?

"Josh" wrote...
I have columns of known y's and a column of known x's whose relationship
follows a power series regression. I found Excel's FORECAST, and GROWTH
functions that will return a y for a given x using a linear regression and
a exponential regression, respectively. Is there such a way to extract a
value using a power regression?

Always hesitate before answering technical questions posed by people who
don't seem to have experience in the field. A basic course on applied
statistics would have gone over the standard data transformations.

If you mean you have a functional form like

y(x) = a * x ^ b

and you want to find estimators for a and b, then log-transform the data,

ln(y(x)) = ln(a) + b * ln(x)

then use FORECAST or GROWTH to fit this linear relationship, and if
necessary calculate the estimator for a as EXP(estimator_for_ln(a)).