Đáp án:
`1.`
`-3|x-5|=-15`
`<=>|x-5|=-15:-3`
`<=>|x-5|=5`
`<=>`\(\left[ \begin{array}{l}x-5=5\\x-5=-5\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x=5+5\\x=-5+5\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x=10\\x=0\end{array} \right.\)
Vậy `x=0` hoặc `x=10`
`2.`
`(2x-1).(x+5)=0`
`<=>`\(\left[ \begin{array}{l}2x-1=0\\x+5=0\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}2x=1\\x=0-5\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x=\dfrac{1}{2}\\x=-5\end{array} \right.\)
Vậy `x=1/2` hoặc `x=-5`
`3.`
`7x-5=13-5x`
`<=>7x+5x=13+5`
`<=>12x=18`
`<=>x=(18)/(12)`
`<=>x=3/2`
Vậy `x=3/2`
`4.`
`2-3x=5x+10`
`<=>-3x-5x=10-2`
`<=>-8x=8`
`<=>x=8:(-8)`
`<=>x=-1`
Vậy `x=-1`
`5.`
`2x-(5-3x)=19-5x`
`<=>2x-5+3x=19-5x`
`<=>2x+3x+5x=19+5`
`<=>10x=24`
`<=>x=24/10`
`<=>x=12/5`
Vậy `x=12/5`
`6.`
`5x+3+(3x-4)=7x-(3x+7)`
`<=>5x+3+3x-4=7x-3x-7`
`<=>5x+3x-7x+3x=-7+4-3`
`<=>4x=-6`
`<=>x=-6/4`
`<=>x=-3/2`
Vậy `x=-3/2`
`7.`
`5(x+3)-7x=12`
`<=>5x+15-7x=12`
`<=>15-12=7x-5x`
`<=>2x=3`
`<=>x=3/2`
Vậy `x=3/2`
