please solve question no 7 on page

Let x be a continuous random variable with the following pidif fox ) = Q - * I 70 a Verify that fox) is the pidif of a random variable ie verify pdif properties for for ) b Find the cidif of X. 8 . Let X be a continuous random variable Juch that E ( ( x- a)?) 4 for all d. Show that E ( ( x -a ) ? ) is minimized when a = tex. Hint : E ( ( x - a) = E ( ( X - E(x ) + ( E ( x ) - a )) D Try to minimize this expression