Highlight a spreadsheet cell to hold x the result of the final equation cell C12 labeled B in Figure 5. Excel trendline equation is correct only in scatter charts. TEXT B10000 - Average TEXT B14000 Then create this formula in say A18.
Its a toggle button so you can click on it again to make the formulas be replaced by its calculated result.
Enter X values of interest into A2 through A5. Its a toggle button so you can click on it again to make the formulas be replaced by its calculated result. With a quick key combination you can see formulas instead of formula results in a worksheet. We will now add the equation of the chart by right clicking on any of the point on the chart select add trendline then scroll down and finally select Display Equation on Chart.