mn giúp mik với

ai nhanh nhất mik cho 5 sao

nhanh hộ mik với

\(A\le\sqrt{3\left(x+y+y+z+z+x\right)}=\sqrt{6\left(x+y+z\right)}\le\sqrt{6.\sqrt{3\left(x^2+y^2+z^2\right)}}=\sqrt{6\sqrt{3}}\)

\(A_{max}=\sqrt{6\sqrt{3}}\) khi \(x=y=z=\dfrac{1}{\sqrt{3}}\)

Do \(x^2+y^2+z^2=1\Rightarrow0\le x;y;z\le1\)

\(\Rightarrow\left\{{}\begin{matrix}x^2\le x\\y^2\le y\\z^2\le z\end{matrix}\right.\) \(\Rightarrow x+y+z\ge x^2+y^2+z^2=1\)

\(A^2=2\left(x+y+z\right)+2\sqrt{\left(x+y\right)\left(x+z\right)}+2\sqrt{\left(x+y\right)\left(y+z\right)}+2\sqrt{\left(y+z\right)\left(z+x\right)}\)

\(A^2=2\left(x+y+z\right)+2\sqrt{x^2+xy+yz+zx}+2\sqrt{y^2+xy+yz+zx}+2\sqrt{z^2+xy+yz+zx}\)

\(A^2\ge2\left(x+y+z\right)+2\sqrt{x^2}+2\sqrt{y^2}+2\sqrt{z^2}=4\left(x+y+z\right)\ge4\)

\(\Rightarrow A\ge2\)

\(A_{min}=2\) khi \(\left(x;y;z\right)=\left(0;0;1\right)\) và các hoán vị

Khi \(x=-\frac{7}{4}\)

\(A=\left(2x-3\right):\left(x+\frac{7}{4}\right)\)

\(\Rightarrow A=\left(2.\left(-\frac{7}{4}\right)-3\right):\left(-\frac{7}{4}+\frac{7}{4}\right)\)

\(\Rightarrow A=\left(2.\left(-\frac{7}{4}\right)-3\right):0\)

\(\Rightarrow A=0\)

tíc mình nha

| x + 93 | + | -y + 17 | = 0

=> x + 93 = 0 và -y + 17 = 0

+) x + 93 = 0 => x = -93

+) -y + 17 = 0 => -y = -17 => y = 17

Vây x = -93, y = 17

con do lam dung day

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