To solve a polynomial equation in Excel, you can use the Goal Seek feature. To do this, enter the equation into a cell and then select the cell. Go to the Data tab and select the What-If Analysis drop-down menu. Select Goal Seek. In the Goal Seek dialog box, enter the cell containing the equation in the Set Cell field, enter the desired result in the To Value field, and enter the cell containing the variable in the By Changing Cell field. Click OK and Excel will solve the equation.
