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thihanh7a1


[TEX]Timf x bieets:[/TEX]
[TEX]10x^2+20y^2+8x+20xy-20y+54\leq:khi (155)::khi (155)::khi (91)::khi (91):[/TEX]
[TEX]10x^2+20y^2+8x+20xy-20y+54\leq:khi (155)::khi (155)::khi (91)::khi (91):[/TEX]