@py
Bài làm :
`|2.x+4|=6`
⇔ \(\left[ \begin{array}{l}2.x+4=6\\2.x+4=-6\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}2x=2\\2x=-10\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=1\\x=-5\end{array} \right.\)
Vậy `x∈{1;-5}`
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`|2-3.x|=5`
⇔ \(\left[ \begin{array}{l}2-3.x=5\\2-3.x=-5\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}3.x=-3\\3.x=7\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=-1\\x=2,333... ( loại )\end{array} \right.\)
Vậy `x=-1`
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`|7-x|=9`
⇔ \(\left[ \begin{array}{l}7-x=9\\7-x=-9\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=-2\\x=16\end{array} \right.\)
Vậy `x∈{-2;16}`
