\(\sqrt{x^2}=\left|-9\right|\)
\(\Leftrightarrow\sqrt{x^2}=9\)
\(\Leftrightarrow x^2=9^2\)
\(\Leftrightarrow x^2=81\)
\(\Leftrightarrow\left[{}\begin{matrix}x=9\\x=-9\end{matrix}\right.\)
Vậy ........................
\(\sqrt{x^2}=\left|-9\right|\)
\(\Leftrightarrow x^2=\pm9^2\)
\(\Leftrightarrow x=\pm9\)
\(Vậy\) \(\left[{}\begin{matrix}x=9\\x=-9\end{matrix}\right.\)
G.sử x, y là các số thực thoả mãn: \(\left(x+\sqrt{3+x^2}\right)\left(y+\sqrt{3+y^2}\right)=9\)
Tìm min: \(P=x^2+xy+y^2\)
1) Rút gọn biểu thức
P=\(\left(1-\dfrac{x-3\sqrt{x}}{x-9}\right):\left(\dfrac{\sqrt{x}-3}{2-\sqrt{x}}+\dfrac{\sqrt{x}-2}{3+\sqrt{x}}-\dfrac{9-x}{x+\sqrt{x}-6}\right)\)
\(P=\left(1-\dfrac{x-3\sqrt{x}}{x-9}\right):\left(\dfrac{9-x}{x+\sqrt{x}+6}-\dfrac{\sqrt{x}-3}{2-\sqrt{x}}-\dfrac{\sqrt{x}-2}{\sqrt{x}+3}\right)\) (rút gọn)
1\(\left\{{}\begin{matrix}xy\left(x+y\right)=2\\x^3+y^3+x^3y^3+7\left(x+1\right)\left(y+1\right)=31\end{matrix}\right.\)
2 giải pt \(9+3\sqrt{x\left(3-2x\right)}=7\sqrt{x}+5\sqrt{3-2x}\)
Tìm x là số thực không âm để \(C=\dfrac{\left(9+2\sqrt{x}\right)}{2+3\sqrt{x}}\varepsilon Z\) là 1 số nguyên
a)\(\left(x^2+\frac{4}{x^2}\right)-4\left(x-\frac{2}{x}\right)-9=0\)
b)\(\left(\sqrt{x+5}-\sqrt{x+2}\right)\left(1+\sqrt{x^2+7x+10}\right)=3\)
A=\(\left(\dfrac{2\sqrt{x}}{\sqrt{x}+3}-\dfrac{\sqrt{x}}{3-\sqrt{x}}-\dfrac{3x+3}{x-9}\right):\left(\dfrac{2\sqrt{x}-2}{\sqrt{x}-3}-1\right)\)
Rút gọn biểu thức trên
\(\left(\frac{1}{\sqrt{x}+3}-\frac{2\sqrt{x}}{x-9}\right):\left(\frac{\sqrt{x}-1}{x-3\sqrt{x}}-\frac{2}{\sqrt{x}}\right)\)
Giải hệ phương trình:
1. \(\left\{{}\begin{matrix}x+3=2\sqrt{\left(3y-x\right)\left(y+1\right)}\\\sqrt{3y-2}-\sqrt{\dfrac{x+5}{2}}=xy-2y-2\end{matrix}\right.\)
2. \(\left\{{}\begin{matrix}\sqrt{2y^2-7y+10-x\left(y+3\right)}+\sqrt{y+1}=x+1\\\sqrt{y+1}+\dfrac{3}{x+1}=x+2y\end{matrix}\right.\)
3. \(\left\{{}\begin{matrix}\sqrt{4x-y}-\sqrt{3y-4x}=1\\2\sqrt{3y-4x}+y\left(5x-y\right)=x\left(4x+y\right)-1\end{matrix}\right.\)
4. \(\left\{{}\begin{matrix}9\sqrt{\dfrac{41}{2}\left(x^2+\dfrac{1}{2x+y}\right)}=3+40x\\x^2+5xy+6y=4y^2+9x+9\end{matrix}\right.\)
5. \(\left\{{}\begin{matrix}\sqrt{xy+\left(x-y\right)\left(\sqrt{xy}-2\right)}+\sqrt{x}=y+\sqrt{y}\\\left(x+1\right)\left[y+\sqrt{xy}+x\left(1-x\right)\right]=4\end{matrix}\right.\)
6. \(\left\{{}\begin{matrix}x^4-x^3+3x^2-4y-1=0\\\sqrt{\dfrac{x^2+4y^2}{2}}+\sqrt{\dfrac{x^2+2xy+4y^2}{3}}=x+2y\end{matrix}\right.\)
7. \(\left\{{}\begin{matrix}x^3-12z^2+48z-64=0\\y^3-12x^2+48x-64=0\\z^3-12y^2+48y-64=0\end{matrix}\right.\)
tìm X
\(\left(\sqrt{20-x^2}+\sqrt{9-x^2}\right)-9+x^2=\left(2\sqrt{5}+x\right)^2\)
giúp với :)))))))))))0
