Đáp án-Giải thích các bước giải:
`(x+1).(3-x) =0 `
`<=>`\(\left[ \begin{array}{l}x+1=0\\3-x=0\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x=-1\\x=3\end{array} \right.\)
Vậy `x=-1; x=3`
______________________________________
`2.|x|+5=32-13`
`<=>2.|x|+5=19`
`<=>2.|x|=14`
`<=>|x|=7`
`<=>x=+-7`
Vậy `x=7;x=-7`
_______________________________________
`|2x+1|-9=-2`
`<=>|2x+1|=7`
`<=>` \(\left[ \begin{array}{l}2x+1=7\\2x+1=-7\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}2x=6\\2x=-8\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x=3\\x=-4\end{array} \right.\)
Vậy `x=3;x=-4`
