`1.`
`15/8 - 1/8 : (x/4 - 0,5) = 5/4`
$\Leftrightarrow$ `1/8 : (x/4 - 1/2) = 15/8 - 5/4`
$\Leftrightarrow$ `1/8 : (x/4 - 1/2) = 15/8 - 10/8`
$\Leftrightarrow$ `1/8 : (x/4 - 1/2) = 5/8`
$\Leftrightarrow$ `(x/4 - 1/2) = 1/8 : 5/8`
$\Leftrightarrow$ `(x/4 - 1/2) = 1/8 . 8/5`
$\Leftrightarrow$ `x/4 - 1/2 = 1/5`
$\Leftrightarrow$ `x/4 = 1/5 + 1/2`
$\Leftrightarrow$ `x/4 = 2/10 + 5/10`
$\Leftrightarrow$ `x/4 = 7/10`
$\Leftrightarrow$ `10x = 7.4`
$\Leftrightarrow$ `10x = 28`
$\Leftrightarrow$ `x = 28 : 10`
$\Leftrightarrow$ `x = 2,8`
$\text{Vậy}$ `x = 2,8`
