ko có x để B= 1/2

\(\left(\sqrt{x+5}-\sqrt{x+2}\right)\left(1+\sqrt{x^2+7x+10}\right)=3.\)

\(\Rightarrow\left(\sqrt{x+5}-\sqrt{x+2}\right)\left(1+\sqrt{\left(x+2\right)\left(x+5\right)}\right)=3\)

Đặt : \(\sqrt{x+5}=a\Rightarrow x+5=a^2\)

\(\sqrt{x+2}=b\Rightarrow x+2=b^2\)\(\left(đk:a,b\ge0\right)\)

\(\Rightarrow a^2-b^2=x+5-x-2=3\left(1\right)\)

Mà theo phương trình, ta có :

\(\left(a-b\right)\left(1+ab\right)=3\)

\(\Rightarrow a+a^2b-b-ab^2=3\)\(\left(2\right)\)

Tự giải hệ 

\(\Leftrightarrow1+\sqrt{x^2+7x+10}=\sqrt{x+5}+\sqrt{x+2}\)

\(\Leftrightarrow\sqrt{x^2+7x+10}-2-\sqrt{x+5}+2-\sqrt{x+2}+1=0\)

\(\Leftrightarrow\frac{\left(x+1\right)\left(x+6\right)}{\sqrt{x^2+7x+10}+2}+\frac{x+1}{2+\sqrt{x+5}}+\frac{x+1}{1+\sqrt{x+2}}=0\)

\(\Leftrightarrow\left(x+1\right)\left(\frac{x+6}{\sqrt{x^2+7x+10}+2}+\frac{1}{2+\sqrt{x+5}}+\frac{1}{1+\sqrt{x+2}}\right)=0\)

Giải nốt nhá ^.^

n là tham số hay sao ah? 

Anh quên mất  \(n\ge0\)

Trả lời 

4H₂O + NaOH------> OH^- + [ Na ( H₂O )₄ ] ⁺

Cũng không chắc nx

Study well 

Trả lời

H2O (nước) + NaOH (natri hidroxit)

= [NA(H2O)4] (Tetraaquasodium ion)

\(\sqrt{2}A=\sqrt{4+2\sqrt{3}}-\sqrt{12-6\sqrt{3}}+\frac{2}{\sqrt{3}+1}\)

\(\sqrt{2}A=\sqrt{3}+1-3+\sqrt{3}+\frac{2}{1+\sqrt{3}}\)

\(\sqrt{2}A=2\sqrt{3}-2+\frac{2}{1+\sqrt{3}}\)

\(A=\sqrt{6}-\sqrt{2}+\frac{\sqrt{2}}{1+\sqrt{3}}=\frac{3\sqrt{6}-3\sqrt{2}}{2}\)