[tex]\it Pentru\ \ x,\ y \in\mathbb{R},\ cu\ proprietatea\\ \\ x^2+y^2-3(x-y)+4,25=0,\\ \\ s\breve{a}\ se\ arate\ c\breve{a}:\\ \\ a)\ |x+y|\geq1\\ \\ b)\ |x^3+y^3|\leq7[/tex]

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