А) х-87-37-20=х-144; Б) (689-b)-(321+c)=689-321-b-c=368-b-c B) 2076-(307+(74+d))=2076-(307+74+d)=2076-307-74-d=1695-d
A) х-144 b) 368 - b - c c) 2076 - (307+(74+d) 2076 - (307 + 74 + d) 2076 - 307 - 74 - d 1695 - d