Question

2. rút gọn

\(x-2y-\sqrt{x^2-4xy+4y^2}\)

Answer 1

\(x-2y-\sqrt{x^2-4xy+4y^2}\left(1\right)=x-2y-\sqrt{\left(x-2y\right)^2}=x-2y-\left|x-2y\right|\)

TH1: \(x\ge2y\)

\(\left(1\right)=x-2y-x+2y=0\)

TH2: \(x< 2y\)

\(\left(1\right)=x-2y+x-2y=2x-4y\)

Answer 2

= x - 2y - \(\sqrt{\left(x-2y\right)^2}\)

= x - 2y - /x-2y/

= x - 2y - x + 2y

= 0

Answer 3

\(x-2y-\sqrt{x^2-4xy+4y^2}\)

\(=x-2y-\left|x-2y\right|\)

\(=\left[{}\begin{matrix}x-2y-x+2y=0\left(x\ge2y\right)\\x-2y+x-2y=2x-4y\left(x< 2y\right)\end{matrix}\right.\)