pt <=> [TEX]3\sqrt{3x+x^2} = -x^2-3x+10[/TEX]
<=> [TEX]x^2+3x+3\sqrt{3x+x^2}-10=0[/TEX]
Đặt [TEX]\sqrt{3x+x^2}=a[/TEX] ( [TEX]a \geq 0[/TEX] )
pt <=>[TEX] a^2+3a-10=0[/TEX]
<=> [TEX](a+5)(a-2)=0[/TEX]
<=> [TEX](\sqrt{3x+x^2}+5)(\sqrt{3x+x^2}-2)=0[/TEX]
<=> [TEX]x^2+3x-4=0[/TEX]
<=> [TEX]x = (1;-4) [/TEX]
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