Ответ:

5,6<=a<=5,8

12,1<=b<=12,2

P=2*(a+b), значит все части неравенств складываем

(5,6+12,1)<=(a+b)<=(5,8+12,2)

получится 17,7<=(a+b)<=18  и умножаем на 2

35,4<=2(a+b)<=36

                                                                                                           т.е. 35,4<=P<=36

s=a*b

5,6*12,1<=a*b<=5,8*12,2

                                                                                                       т.е. 67,76<=S<=70,76