7.5 ???)8? 25 ??0?(?0???????? 20,000 ?? ???(0??????? ?????? A = L + OE (P) ?(0??????? ?8???) ??????3? ?,??????8?4? 7.6 ???)8? 28 ?????)9???(?,???? 1,500 ?? ???(0??????? ?????? A = L + OE (P) ?(?? ???? ? ?8???) ??????3? ?,??????8?4? . ? ? . ? ?