Đáp án:
Giải thích các bước giải:
Bài 3 :
a,
`-12(x-5)+7(3-x)=5`
`->-12x+60+21-7x=5`
`->-12x-7x=5-60-21`
`->-19x=-76`
`->x=4`
b,
`30(x+2)-6(x-5)-24x=10`
`->30x+60-6x+30-24x=10`
`->30x-6x-24x=10-60-30`
`->0x=-80` ( vô lí )
`->x \in ∅`
g,
`7x-1+3x-2=-23`
`->7x+3x=-23+1+2`
`->10x=-20`
`->x=-2`
h,
`4x-5-6x+7=-18`
`->4x-6x=-18+5-7`
`->-2x=-20`
`->x=10`
Bài 4 :
a,
`|x|=17-3`
`->|x|=14`
`->` \(\left[ \begin{array}{l}x=14\\x=-14\end{array} \right.\)
b,
`|x|=4`
`->` \(\left[ \begin{array}{l}x=4\\x=-4\end{array} \right.\)
c,
`|x-1|=10`
`->` \(\left[ \begin{array}{l}x-1=10\\x-1=-10\end{array} \right.\)
`->` \(\left[ \begin{array}{l}x=10+1\\x=-10+1\end{array} \right.\)
`->` \(\left[ \begin{array}{l}x=11\\x=-9\end{array} \right.\)
d,
`|2x-5|=13`
`->` \(\left[ \begin{array}{l}2x-5=13\\2x-5=-13\end{array} \right.\)
`->` \(\left[ \begin{array}{l}2x=13+5\\2x=-13+5\end{array} \right.\)
`->` \(\left[ \begin{array}{l}2x=18\\2x=-8\end{array} \right.\)
`->` \(\left[ \begin{array}{l}x=9\\x=-4\end{array} \right.\)
