câu 1 : Giải pt sau
a . \(2x-2\sqrt{2x}-1=0\)
câu 2 : thu gọn các biểu thức sau
\(A=\frac{3+\sqrt{5}}{3-\sqrt{5}}+\frac{3-\sqrt{5}}{3+\sqrt{5}}\)
\(B=\sqrt{12-6\sqrt{3}}+\sqrt{21-12\sqrt{3}}\)
\(C=5\left(\sqrt{2+\sqrt{3}}+\sqrt{3-\sqrt{5}}-\sqrt{\frac{5}{2}}\right)^2+\left(\sqrt{2-\sqrt{3}}+\sqrt{3+\sqrt{5}}-\sqrt{\frac{3}{x}}\right)^2\)
1) ĐK:x\(\ge\frac{1}{2}\)
PT\(\Leftrightarrow\sqrt{2x-1}=x\)
\(\Leftrightarrow\begin{cases}x\ge0\\2x-1=x^2\end{cases}\)
\(\Leftrightarrow\begin{cases}x\ge0\\x=1\end{cases}\)
\(\Leftrightarrow x=1\) (thỏa mãn)
\(A=\frac{\left(3+\sqrt{5}\right)^2+\left(3-\sqrt{5}\right)^2}{\left(3+\sqrt{5}\right)\left(3+\sqrt{5}\right)}\)
\(A=\frac{18+10}{4}\)
\(A=7\)