`(x+y)^2 -2(x+y)(x-y)+(x-y)^2`

\(=\left[\left(x+y\right)-\left(x-y\right)\right]^2\\ =\left(x+y-x+y\right)^2\\ =\left(2y\right)^2\\ =4y^2\)

\(\dfrac{27^2-9^2+3^3}{25}\\ =\dfrac{\left(3^3\right)^2-\left(3^2\right)^2+3^3}{25}\\ =\dfrac{3^6-3^4+3^3}{25}\\ =\dfrac{3^3\left(3^3-3+1\right)}{25}\\ =\dfrac{3^3\left(27-3+1\right)}{25}\\ =\dfrac{3^3\cdot25}{25}\\ =3^3=27\)

`6` hay `9` ạ?

\(\dfrac{1}{2}-3x+\left|x-1\right|=0\\ \Rightarrow3x+\left|x-1\right|=\dfrac{1}{2}-0\\ \Rightarrow3x+\left|x-1\right|=\dfrac{1}{2}\\ \Rightarrow\left|x-1\right|=\dfrac{1}{2}-3x\\ \Rightarrow\left[{}\begin{matrix}x-1=\dfrac{1}{2}-3x\\x-1=-\dfrac{1}{2}+3x\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x+3x=\dfrac{1}{2}+1\\x-3x=-\dfrac{1}{2}+1\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}4x=\dfrac{3}{2}\\2x=\dfrac{1}{2}\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{3}{8}\\x=\dfrac{1}{4}\end{matrix}\right.\)

__

\(\dfrac{1}{2}\left|2x-1\right|+\left|2x-1\right|=x+1\\ \Rightarrow\left|2x-1\right|\cdot\left(\dfrac{1}{2}+1\right)=x+1\\ \Rightarrow\left|2x-1\right|\cdot\dfrac{3}{2}=x+1\\ \Rightarrow\left|2x-1\right|=x+1:\dfrac{3}{2}\\ \Rightarrow\left|2x-1\right|=x+\dfrac{2}{3}\\ \Rightarrow\left[{}\begin{matrix}2x-1=x+\dfrac{2}{3}\\2x-1=-x-\dfrac{2}{3}\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}2x-x=\dfrac{2}{3}+1\\2x+x=-\dfrac{2}{3}+1\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{5}{3}\\3x=\dfrac{1}{3}\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{5}{3}\\x=\dfrac{1}{9}\end{matrix}\right.\)

`9,48 : 4 + 9,48 xx 0,75`

`= 9,48 xx 1/4 + 9,48 xx 0,75`

`=  9,48 xx 0,25 + 9,48 xx 0,75`

`=  9,48 xx ( 0,25 +  0,75)`

`= 9,48 xx 1`

`=9,48`

Đúng đề hả c?

thoi toy k chứa cậu nuaa=))

\(a\left(\sqrt{2}-1\right)+b\left(\sqrt{2}+1\right)=12\\ \Leftrightarrow a\sqrt{2}-a+b\sqrt{2}+b=12\)

Đề như vậy á cậu?