Giải thích các bước giải:
1) `(ĐKXĐ:x\ne 0;x\ne 2)`
`P=(\frac{x-1}{x^2-2x}+\frac{x+1}{x^2+2x}-\frac{4}{x^3-4x}):(1-\frac{2}{x})`
`=[(x-1)/[x(x-2)]+(x+1)/[x(x+2)``-4/[x(x+2)(x-2)]]:(x-2)/x`
`=\frac{(x-1)(x+2)+(x+1)(x-2)-4}{x(x+2)(x-2)}.\frac{x}{x-2}`
`=\frac{x^2+x-2+x^2-x-2-4}{x(x+2)(x-2)}.\frac{x}{x-2}`
`=\frac{2(x+2)(x-2)}{(x-2)(x+2)(x-2)}`
`=\frac{2}{x-2}`
2) `|2x-1|=5`
`->` \(\left[ \begin{array}{l}2x-1=5\\2x-1=-5\end{array} \right.\)
`->` \(\left[ \begin{array}{l}2x=6\\2x=-4\end{array} \right.\)
`->` \(\left[ \begin{array}{l}x=3\\x=-2\end{array} \right.\)
`Với` `x=3(tm)` `->` `P=2/(3-2)=2/1=2`
`Với` `x=-2(tm)` `->` `P=2/(-2-2)=-1/2`
3) `Để` `P>0`
`->` `\frac{2}{x-2}>0`
`->` `x-2>0` `(` `vì` `2>0` `)`
`->` `x>2(tm)`
