[已識計！]Add.M. binomial 1題 plz help

when (2(x^3) - 1/3x))^n is expanded in descending powers of x, the 7th term is a
constant term.Find the values of n and the constant term.

就係呢題啦
我唔知第1步做d咩
你你地解釋下步驟應該係點
唔洗成題做晒

[[i] 本帖最後由 Lok^yan(印 於 2007-10-8 07:55 PM 編輯 [/i]]