Question

[Đinh Cẩm Tú]

Giải PT:

a) \(\sqrt{11+6\sqrt{2}}\) = \(\sqrt{2x^2-6x\sqrt{2}+9}\)

b) \(\sqrt{4x^2+4x\sqrt{7}+7}\) - \(\sqrt{8-2\sqrt{7}}\) = 0

c) \(\sqrt{x^2}\) = x

d) \(\sqrt{x^2-2x+1}\) = x-1

Answer 1

[Nguyễn Lê Phước Thịnh]

c: Ta có: \(\sqrt{x^2}=x\)

\(\Leftrightarrow\left|x\right|=x\)

hay \(x\ge0\)

d: Ta có: \(\sqrt{x^2-2x+1}=x-1\)

\(\Leftrightarrow\left|x-1\right|=x-1\)

hay \(x\ge1\)