Bài $5$ :
`a)A=8/15+(-9)/10-7/6`
`A=-55/150-7/6`
`A=-1285/900`
`B=4/15 . 3/7+4/15 . (-17)/7 -4/15`
`B=4/15.(3/7+(-17)/7-1)`
`B=4/15 . -3`
`B=-4/5`
Bài $6$ :
`x(1/2-1/3)=(-25)/6`
`x 1/6=(-25)/6`
`x=(-25)/6:1/6`
`x=-25`
`b)2.|x-1|-3=5`
`2.|x-1|=2`
`|x-1|=1`
$\begin{cases}x-1=1\\-x+1=1\end{cases}$
$↔️\begin{cases}x=2\\x=0\end{cases}$