Update README.md

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

Author: FabianaCampanari

README.md

@@ -675,17 +675,16 @@ x_1 \geq 0, \quad x_2 \geq 0
 
 ### 5. [Complete Mathematical Model]():
 
-$
-\boxed{
+
+$\boxed{
 \begin{cases}
 \text{Maximize } Z = 120x_1 + 150x_2 \\
 2x_1 + 4x_2 \leq 100 \\
 3x_1 \leq 90 \\
 5x_1 + 3x_2 \leq 120 \\
 x_1 \geq 0, \quad x_2 \geq 0
 \end{cases}
-}
-$
+}$