a ) A có nghĩa khi : \(x\ne2;-2.\)
b ) Không chép đề nha .\(A=\dfrac{x+2}{2\left(x-2\right)}-\dfrac{x-2}{2\left(x+2\right)}+\dfrac{8}{\left(x-2\right)\left(x+2\right)}\)
\(A=\dfrac{\left(x+2\right)^2-\left(x-2\right)^2+16}{2\left(x-2\right)\left(x+2\right)}\)
\(A=\dfrac{\left(x+2-x+2\right)\left(x+2+x-2\right)+16}{2\left(x-2\right)\left(x+2\right)}\)
\(A=\dfrac{4.2x+16}{2\left(x-2\right)\left(x+2\right)}\)
\(A=\dfrac{8x+16}{2\left(x-2\right)\left(x+2\right)}=\dfrac{8\left(x+2\right)}{2\left(x-2\right)\left(x+2\right)}=\dfrac{4}{x-2}\)
c ) \(\left|x-3\right|=1\)
\(\Leftrightarrow\left[{}\begin{matrix}x-3=1\\x-3=-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4\\x=2\left(loại\right)\end{matrix}\right.\)
Vậy khi x = 4 thì :
\(A=\dfrac{4}{4-2}=\dfrac{4}{2}=2\)
Vậy .......
