Maths Olympiad Prep

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Algebra Difficulty 6.4 National olympiad Prove it

68. (Original problem, 2006.08.31) Let x,y,z,u,vR+x, y, z, u, v \in \mathbf{R}^{+}, and 3(u+v)xyz3(u+v) x y z \geqslant ux2+vyzu \sum x^{2}+v \sum y z, then
(57u+9v)x3(11u+3v)yz+72u(57 u+9 v) \sum x \leqslant 3(11 u+3 v) \sum y z+72 u

Equality holds if and only if x=y=z=1x=y=z=1.

Solution

None

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