Excel - Looking to reverse a quadratic formula, Sqrt and all??

Asked By DataScheme on 14-Aug-09 08:34 AM
I know there is a trend line avail. with poly fit and you can change to
However when reversing this formula to solve for X there is no help in
excel.  Is there an add in or someone whith a spreadsheet that can help?

Simple Quadratic help would do?

GarysStuden replied on 14-Aug-09 09:17 AM
with the usual coefficients:
a in A1
b in B1
c in C1



For for A1 thru C1:

10	60	30

the formulas return the Real roots:


For non-Real roots you must use more "imaginative" methods.
Gary''s Student - gsnu200860
Joe replied on 14-Aug-09 09:27 AM
Use the quadratic formula

with A in A1, b in B1, c in C1

=-b +/- sqrt(b**2-4ab)



Luke replied on 14-Aug-09 09:36 AM
To calculate non real roots:

Imaginary1 (if needed):
Imaginary2 (if needed):

Best Regards,

Luke M
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