(a)
Arranging the given values in ascending order of magnitude
$x - \frac{7}{2},x - 3,\ x - \frac{5}{2},\ x - 2,\ x + \frac{1}{2},\ x + 4,\ x + 5$
There are 8 observations in the series, therefore
$median = \frac{Value\ of\ 4th\ term + Value\ of\ 5th\ term}{2}$
$= \frac{x - 2 + x - \frac{1}{2}}{2} = x - \frac{5}{4}$