Help me! bài GTLN

T

thatki3m_kut3

A=[TEX]\frac{2x}{\sqrt{x}-2}[/TEX] =[TEX]\frac{16\sqrt{x}-32+2x-16\sqrt{x}+32}{\sqrt{x}-2}[/TEX]
=16+[TEX]\frac{2.(x-8\sqrt{x}+16}{\sqrt{x}-2}[/TEX]
=16+[TEX]\frac{2.(\sqrt{x}-4)^2}{\sqrt{x}-2}[/TEX]\geq16
\RightarrowGTNN A=16 khi [TEX]\sqrt{x}=4[/TEX]\Rightarrowx=16
 
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