[tex]M= -\dfrac{\Delta}{4a} = - \dfrac{\ \Delta}{-4} =\dfrac{\Delta}{4}\ \ \ \ (1)
[/tex]
[tex]Calculam\ \Delta\ si\ obtinem:
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\Delta = -4-3m^2\ \ \ \ (2)[/tex]
[tex](1), (2) \Longrightarrow M = \dfrac{-4-3m^2}{4} =\dfrac{-4}{4} -\dfrac{3m^2}{4} =-1-\dfrac{3m^2}{4} \leq -1[/tex]