By using properties of determinants. Show that:
(i) `|(x+4,2x,2x),(2x,x+4,2x),(2x,2x,x+4)|=(5x-4)(4-x)^2`
(ii) `|(y+k,y,y),(y,y+k,y),(y,y,y+k)|=k^2(3y+k)`