Factorise the following:
(i) ` x^(3) +8y^(3) +6xy -1`
(ii) ` l^(3)-8m^(3) -27n^(3) -18lmn `

Answer

` = (l-2m-3m)(l^(2) +4m^(2) +9n^(2) =2lm -6mn +3ln) `