Sao đang x, y, z lại sang a, b, c vậy

\(\frac{1}{a^2+b^2+c^2}+\frac{2018}{ab+bc+ca}=\frac{1}{a^2+b^2+c^2}+\frac{1}{ab+ac+bc}+\frac{2017}{ab+ac+bc}\)

\(=\frac{1}{a^2+b^2+c^2}+\frac{2}{2ab+2ac+2bc}+\frac{2017}{ab+ac+bc}\ge\frac{\left(1+2\right)^2}{\left(a+b+c\right)^2}+\frac{2017}{\frac{\left(a+b+c\right)^2}{2}}=\frac{9}{3}+\frac{2017.2}{9}\)

\(A=\frac{\sqrt{x}+1}{\sqrt{x}-1}=\frac{\sqrt{4+2\sqrt{3}}+1}{\sqrt{4+2\sqrt{3}}-1}\)\(=\frac{\sqrt{\left(\sqrt{3}\right)^2+2\cdot\sqrt{3}\cdot1+1^2}+1}{\sqrt{\left(\sqrt{3}\right)^2+2\cdot\sqrt{3}\cdot1+1^2}-1}\)

\(=\frac{\sqrt{\left(\sqrt{3}+1\right)^2}+1}{\sqrt{\left(\sqrt{3}+1\right)^2}-1}=\frac{\sqrt{3}+1+1}{\sqrt{3}+1-1}=\frac{\sqrt{3}+2}{\sqrt{3}}=\frac{\left(\sqrt{3}+2\right)\sqrt{3}}{\sqrt{3}\cdot\sqrt{3}}\)\(=\frac{3+2\sqrt{3}}{3}\)

ket ban voi mk nha

\(m_{dd}=\frac{m_{ct}}{C_{\%}}\times100\)

khối lượng dung dịch thì bằng tổng khối lượng chất tham gia trừ đi khối lượng chất kết tủa và bay hơi nếu có trong dung dịch sau phản ứng. 

\(P=\frac{1}{x^2-\sqrt{x}}:\frac{\sqrt{x}+1}{x\sqrt{x}+x+\sqrt{x}}\)\(=\frac{1}{\sqrt{x}\left(\sqrt{x^3}-1^3\right)}:\frac{\sqrt{x}+1}{\sqrt{x}\left(x+\sqrt{x}+1\right)}\)

\(\frac{1}{\sqrt{x}\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}\cdot\frac{\sqrt{x}\left(x+\sqrt{x}+1\right)}{\sqrt{x}+1}\)\(\frac{1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}=\frac{1}{x-1}\)

2) De 3P=1+x

=> \(3\left(\frac{1}{x-1}\right)=x+1\)<=>\(\frac{3}{x-1}=x+1\)<=>\(\left(x+1\right)\left(x-1\right)=3\)

<=> \(x^2-1=3\)<=> \(x^2=4\)<=> \(x=2\)hoac \(x=-2\)

Vay voi x =2 va x=-2 ta co 3P=x+1