\(\sqrt{2x+1}=3\)
ĐKXĐ: \(x\ge-\frac{1}{2}\)
\(\Leftrightarrow\left(\sqrt{2x+1}\right)^2=3^2\\ \Leftrightarrow2x+1=9\\ \Leftrightarrow2x=8\Leftrightarrow x=4\)
(t/m ĐK)
Vậy x = 4
\(\sqrt{2x+1}=3\)
\(\Rightarrow\sqrt{2x+1}=\left(\sqrt{3}\right)^2\)
\(\Rightarrow\sqrt{2x+1}=\sqrt{9}\)
\(\Rightarrow2x+1=9\)
\(\Rightarrow2x=9-1\)
\(\Rightarrow2x=8\)
\(\Rightarrow x=8:2\)
\(\Rightarrow x=4\)
Vậy \(x=4.\)
Chúc bạn học tốt!