Đáp án + Giải thích các bước giải:
`a//|2x+2|=15`
`->` \(\left[ \begin{array}{l}2x+2=15\\2x+2=-15\end{array} \right.\)
`->` \(\left[ \begin{array}{l}2x=15-2\\2x=-15-2\end{array} \right.\)
`->` \(\left[ \begin{array}{l}2x=13\\2x=-17\end{array} \right.\)
`->` \(\left[ \begin{array}{l}x=13:2\\x=-17:2\end{array} \right.\)
`->` \(\left[ \begin{array}{l}x=\frac{13}{2}\\x=-\frac{17}{2}\end{array} \right.\)
Vậy `x∈{(13)/(2);-(17)/(2)}`
`b//|x-8|=20`
`→` \(\left[ \begin{array}{l}x-8=20\\x-8=-20\end{array} \right.\)
`→` \(\left[ \begin{array}{l}x=20+8\\x=-20+8\end{array} \right.\)
`→` \(\left[ \begin{array}{l}x=28\\x=-12\end{array} \right.\)
Vậy `x∈{28;-12}`
