Đáp án + Giải thích các bước giải: 1/ `|x – 7| = 0 => x – 7 = 0=> x=7` 2/`|x + 3| = 6 => `\(\left[ \begin{array}{l}x + 3=6\\x+3=-6\end{array} \right.\) $\\$ `=>` \(\left[ \begin{array}{l}x=3\\x=-9\end{array} \right.\) 3/ `|2x + 4| + 15= 35` $\\$ `=> |2x + 4| = 35 – 15` $\\$ `=> |2x + 4| = 20` $\\$ `=>` \(\left[ \begin{array}{l}2x+4=20\\2x + 4 = -20\end{array} \right.\) $\\$ `=>` \(\left[ \begin{array}{l}2x=16\\2x=-24\end{array} \right.\) $\\$ `=>` \(\left[ \begin{array}{l}x=8\\x=-12\end{array} \right.\) Bình luận
`1)|x-7|=0` `x-7=0` `x=-7` Vậy `x in{-7}`. `2)|x+3|=6` \(\left[ \begin{array}{l}x+3=6\\x+3=-6\end{array} \right.\) \(\left[ \begin{array}{l}x=3\\x=-9\end{array} \right.\) Vậy `x in{3;-9}`. `3)|2x+4|+15=35` `|2x+4|=20` \(\left[ \begin{array}{l}2x+4=20\\2x+4=-20\end{array} \right.\) \(\left[ \begin{array}{l}x=8\\x=-12\end{array} \right.\) Vậy `x in{8;-12}`. Bình luận
Đáp án + Giải thích các bước giải:
1/ `|x – 7| = 0 => x – 7 = 0=> x=7`
2/`|x + 3| = 6 => `\(\left[ \begin{array}{l}x + 3=6\\x+3=-6\end{array} \right.\) $\\$ `=>` \(\left[ \begin{array}{l}x=3\\x=-9\end{array} \right.\)
3/ `|2x + 4| + 15= 35` $\\$ `=> |2x + 4| = 35 – 15` $\\$ `=> |2x + 4| = 20` $\\$ `=>` \(\left[ \begin{array}{l}2x+4=20\\2x + 4 = -20\end{array} \right.\) $\\$ `=>` \(\left[ \begin{array}{l}2x=16\\2x=-24\end{array} \right.\) $\\$ `=>` \(\left[ \begin{array}{l}x=8\\x=-12\end{array} \right.\)
`1)|x-7|=0`
`x-7=0`
`x=-7`
Vậy `x in{-7}`.
`2)|x+3|=6`
\(\left[ \begin{array}{l}x+3=6\\x+3=-6\end{array} \right.\)
\(\left[ \begin{array}{l}x=3\\x=-9\end{array} \right.\)
Vậy `x in{3;-9}`.
`3)|2x+4|+15=35`
`|2x+4|=20`
\(\left[ \begin{array}{l}2x+4=20\\2x+4=-20\end{array} \right.\)
\(\left[ \begin{array}{l}x=8\\x=-12\end{array} \right.\)
Vậy `x in{8;-12}`.