Question

Nghiệm của phương trình căn(x - 2 căn(x - 1)) = 5

Answer 1

\(ĐK:x\ge1\\ PT\Leftrightarrow\sqrt{x-1-2\sqrt{x-1}+1}=5\\ \Leftrightarrow\sqrt{\left(\sqrt{x-1}-1\right)^2}=5\\ \Leftrightarrow\left|\sqrt{x-1}-1\right|=5\Leftrightarrow\left[{}\begin{matrix}\sqrt{x-1}-1=5\left(x\ge2\right)\\1-\sqrt{x-1}=5\left(x< 2\right)\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=37\left(tm\right)\\\sqrt{x-1}=-4\left(ktm\right)\end{matrix}\right.\Leftrightarrow x=37\)