tìm MIN

N

noinhobinhyen

$3(x^4+y^4+z^4) \geq (x^2+y^2+z^2)^2 \geq (xy+xz+yz)^2=12^2=144$

$\Rightarrow MIN_{x^4+y^4+z^4}=48 \Leftrightarrow x=y=z=2$
 
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