How to Solve for x in Excel (2 Simple Ways)

The following dataset has 4 equations, each successively increasing the power of x. We’ll find the value of x in these equations.

how to solve for x in excel

Method 1 – Using Goal Seek to Solve for x in Excel

Step 1 – Formulate the Equation to find F(x) Value

Enter the following formula in cell C5.

=(20*D5)-307

Here, cell D5 refers to the cell of the X Value column.

Press Enter.

Using Goal Seek Feature to Solve For x in Excel

Note: We will be using the cells in Column D as the initial x value. Since there are no values in those cells, the initial x values will be 0 for all the cases.

You will see the following output in cell C5.

Now, enter the following formula in cell C6 to find the F(x) Value for the second equation.

=(D6^2)-(7*D6)+2

Cell D6 represents the cell of the X Value column.

Hit Enter.

You will get the F(x) Value for the second equation.

Insert the corresponding formulas to get the F(x) Values for the rest of the equations.

Step 2 – Apply Goal Seek

Go to the Data tab.
Select the What-If Analysis option.
Choose the Goal Seek option from the drop-down.

The Goal Seek dialog box will open as shown in the following image.

Click on the box of Set cell and select cell C5.
Enter 0 in the To Value box

Click on the By changing cell box and choose cell D5.
Click on OK.

The Goal Seek Status dialog will confirm that it has found a solution.

Click OK.

You will get the x Value for the first equation as demonstrated in the following picture.

Repeat the same procedure for the rest of the values ,and you will get the x Values for other equations.

Method 2 – Applying the Solver Add-in to Solve for x in Excel

Step 1 – Enable the Solver Add-in

Use the keyboard shortcut Alt + F + T to open Excel Options.

Go to the Add-ins tab.
Click on the Go option below the list.

Check the Solver Add-in option.
Click OK.

Go to the Data tab, and you will see that the Solver option is added to the Analyze group.

Step 2 – Formulate the Equation to find the F(x) Value

Use the procedure in Step 1 of Method 1 to get the F(x) Values for the equations.

Step 3 – Utilizing the Solver Add-in Option

Go to the Data tab.
Choose the Analyze option.
Select the Solver option from the drop-down.

The Solver Parameters dialog box will open on your worksheet as shown in the following picture.

Click the arrow on the Set Objective box.

Choose cell C5 under F(x) Value.

In the Solver Parameters dialog box, choose the Value Of option and enter 0 in the box to the right.
Click on the By Changing Variable Cells arrow: