[" Factorise the following expressions."],[[" (i) "p^(2)+6p+8," (ii) "q^(2)-10q+21," (iii) "p^(2)+6p-16,],[" (i) "p^(2)+6p+8," (ii) "q^(2)-10q+21," (iii) "p^(2)+6p-16]]