Polynomial equations up to the third order will be used here, although these methods can also be applied to higher-order polynomials.

### Method 1 – Using the Goal Seek Option

If you know the result of a polynomial, you can use the **Goal Seek **feature to find the input that produces that result.

**Steps:**

- Double-click on
**B7**and enter the following formula:

`=(5*C7^3)-(2*C7^2)+(3*C7)-6`

- Then, enter a value for
**X**in**C5**.

- Go to the
**Data**tab and choose**Forecast**. - In
**What-If****Analysis**, click**Goal seek**.

- Enter the values as in the image below and click
**OK**.

- The
**Goal Seek**option will solve the value for X in Excel.

**Read More:** How to Solve an Equation for X When Y is Given in ExcelÂ

### Method 2 – Utilizing the Solver Feature

The **Solver **tool in Excel uses operations research methods to find the optimal solution from a set of equations.

**Steps:**

- Open the
**Solver**tool in the**Data**tab.

- Enter the following parameters in
**Solver Parameters**.

- Click
**Solve**and the**Solver**will calculate the value of**X**.

### Method 3-Â Solving a Quadratic Polynomials Equation

**Steps:**

- Click
**C9**and enter the formula:

`=(-C7+SQRT(C7^2-4*C6*C8))/(2*C6)`

- Enter this formula in
**C10**:

`=(-C7-SQRT(C7^2-4*C6*C8))/(2*C6)`

- Press
**Enter**to see the solutions of**X**.

**Read More:** How to Solve 2 Equations with 2 Unknowns in Excel

### Method 4 – Finding the Solution of a Multivariable Equation by using the MINVERSE Function

T**he MINVERSE function** in Excel returns the inverse of a given array, but it can be used to solve a multivariable polynomial equation.

**3x+2y+z=8**

**11x+-9y+23=27**

**8x-5y=10**

**Steps:**

- Select the range
**B10:****D12**and enter the following formula:

`=MINVERSE(B5:D7)`

- Press
**Ctrl+Shift+Enter**and you will see the inverse values.

- Select the range
**F10:****F12**and enter the following formula:

`=MMULT(B10:D12,E5:E7)`

- Press
**Ctrl+Shift+Enter**and you will see the values of**x**,**y,**and**z**.

### Method 5 – Using the Solver to Find the Solution of a Multivariable Equation

The **3** equations from the previous method will be used.

**Steps:**

- Double-click
**E5**and enter the formula below:

`=3*C5+2*C6+C7`

- Copy this formula to the cells below using the
**Fill Handle**.

- Click
**F5**and enter this formula:

`=FORMULATEXT(E5)`

- Copy this formula to the cells below.

- Open the
**Solver**and enter the parameters. - To add the
**Constraints**, click**Add**.

- Note that you need to click
**Add**after entering each constraint.

- ClickÂ
**Solve**option to see the solutions.

**Download Practice Workbook**

Download the practice workbook here.

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- How to Solve Exponential Equation in Excel
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- How to Solve Quadratic Equation in Excel VBA

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