Update README.md

Signed-off-by: Fabiana 🚀  Campanari <113218619+FabianaCampanari@users.noreply.github.com>

Author: FabianaCampanari

README.md

@@ -188,7 +188,7 @@ The **graphical method** for solving simple linear programming (LP) problems inv
 
 ### Key Concepts
 
-- **Decision Variables:** These are the variables that we want to determine the values of to optimize the objective function (e.g., $\(x_1\) and \(x_2\)$).
+- **Decision Variables:** These are the variables that we want to determine the values of to optimize the objective function (e.g., $\(x_1\)$ and $\(x_2\)$).
 
 - **Objective Function:** This is the linear function that we aim to maximize or minimize. For example: