Am nevoie rapid va rog , dau coroana || clasa 8

[tex]\it a)\ \ E(x)=x^2+2x+1-x^2+4x-4-4x+2=2x-1\\ \\ \\ b)\ \ E(n)=2n-1\geq-6\Big|_{+1} \Rightarrow 2n\geq-5|_{:2} \Rightarrow n\geq-2,5 \Rightarrow n\in\{-2,\ \ -1,\ \ 0,\ \ 1,\ \ 2,\ \ 3,\ ...\}[/tex]
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