`[6 1/2-(x+1)]:-5/4=2/5`
`=> 13/2 -(x+1) = 2/5 xx (-5/4)`
`=>13/2 -(x+1) = -10/20`
`=> x+1=13/2 +1/2`
`=> x+1=14/2`
`=> x= 7-1`
`=>x=6`
Vậy `x=6`
Lời giải:
$6\frac{1}{2}-(x+1)=\frac{2}{5}.\frac{-5}{4}=\frac{-1}{2}$
$x+1=6\frac{1}{2}-\frac{-1}{2}=7$
$x=7-1=6$