**OpenSolver** is a great **Excel Add-in** that solves optimization models. The following article will describe how to solve a **Linear Programming** model using this tool (first you must **Download and install OpenSolver in Excel**). For educational purposes we will consider a linear programming model with two decision variables and four constraints, nevertheless you can easily extend its application to larger problems.

**Maximize**

**Subject to**:

We will then need to prepare an **Excel** spreadsheet that includes the model’s parameters and variables (this step is similar to loading a problem in * Frontline’s Solver*). You can see that cells

**B2**and

**C2**(

*) have been assigned as the*

**yellow color****decision variables**and cell

**E2**corresponds to the

**objective function**(

*), which is a formula that links the decision variables to their respective parameters. Finally cells*

**blue cell****D5**and

**D6**are formulas that represent the “

**” of the problem’s**

*left-hand side*(LHS)**constraints**(for example, cell

**D5**corresponds to

**B2*B5+C2*C5**or equivalently

**SUMPRODUCT(B2:C2;B5:C5)**).

Once the previous step has been completed you must run **OpenSolver**, whose menu can be accessed from the “**Data**” tab in **Excel**. Then select “**Model…**” as shown below:

The interface for implementing the model is quite similar to the traditional **Solver** (Frontline) version. The * objective cell* is defined (

**E2**) in maximization; next you must select the range of

*(as shown in the following image) and the*

**decision variables***. If you try to replicate the structure of the example we are going over in this article, then it should look like this:*

**constraints**Then we select “**Save Model**” (the structure of the template will change and become different colors, one of the characteristics **OpenSolver** has that makes this Add-in such a intuitive tool for the user).

Finally we select “**Solve**”:

The program is run and gives us the * optimal solution* ( and ) and the

*for the optimization problem:*

**optimal value**The results achieved are consistent with those obtained in the graphical solution of the problem that we went over in the article “**What does a Shadow Price of Zero mean in Linear Programming**” as shown in the following image:

Below you can download the file that contains **OpenSolver’s** solution to this problem so that you can familiarize yourself with this **Excel Add-in**: **OpenSolver Excel**.

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