Update README.md

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

Author: FabianaCampanari

README.md

@@ -190,7 +190,7 @@ The **graphical method** for solving simple linear programming (LP) problems inv
 
 - **Decision Variables:** These are the variables that we want to determine the values of to optimize the ***[OBJECTIVE FUNCTION]()*** (e.g.) -
 
-### $$\(x_1\)$$ and $$\(x_2\)$$
+ $$\(x_1\)$$ and $$\(x_2\)$$
 
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