If the line was put on using Chart|Add Trendline, click on the Options
tab in the Add Trendline dialog and request the "Display equation on chart"

If by "linear line equastion" you mean a simple straight line, look at
help for the SLOPE() and INTERCEPT() functions.

If by "linear line equastion" you mean a model that is linear in the
unkown parameters (polynomials, multiple linear regression, etc) then
use LINEST. Help for LINEST misleads most people into thinking it can
only fit a simple straight line; just pass the array of all X columns.
Bernard Liengme gave a link to his site showing how to do polynomials
with LINEST without having to create a column for each power of x.

Jerry

Dawn wrote:

how do i calcualte a non linear line equation using excel? i have the graph
with the non loinear line on i just need to put the equation on.