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Question

chung minh rang $19x^2+54y^2+16z^2-16xz+36xy-24yz\geq 0$

2,cho 6 so thoa man $mx^2+2nx+p\geq 0,ax^2+bx+c\geq 0$ chung minh rng $max^2+2nbx+pc\geq 0$

vs moi x

๖ۣۜTQT☾♋☽ · Answer 1 · 1/26/2016 4:31:38 PM

$=( 9x^2 +36xy +36y^2 ) +(18y^2 -24yz + 8z^2)+ (8x^2 +16xz + 8z^2) + 2x^2 +5 \geqslant 0$

$\Leftrightarrow 9(x+2y)^2 + 2(3y - 2z)^2 + 8(x-z)^2 + 2x^2 + 5\geqslant 0$

$\Rightarrow :đpcm$

Sửa 26-01-16 04:31 PM

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Trả lời 26-01-16 04:17 PM

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