Ai giải giùm mình 2 bài này với :)

P

popstar1102


$\sqrt{x^2-4}$-$\sqrt{x+2}$=0

\Leftrightarrow$\sqrt{x-2}$.$\sqrt{x+2}$-$\sqrt{x+2}$=0

\Leftrightarrow$\sqrt{x+2}$($\sqrt{x-2}$-1)=0

\Rightarrowx=-2;x=3
 
P

popstar1102


x+y+4=2$\sqrt{x}$+4$\sqrt{y}$-1

\Leftrightarrowx- 2$\sqrt{x}$+1+y- 4$\sqrt{y}$+4=0

\Leftrightarrow$({\sqrt{x}}-1)^2$+$({\sqrt{y}}-2)^2$=0

vì $({\sqrt{x}}-1)^2$ \geq 0

$({\sqrt{y}}-2)^2$ \geq 0

\Rightarrow$\sqrt{x}$-1=0\Rightarrowx=1

$\sqrt{y}$-2=0\Rightarrowy=4
 
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