11•(60+а); 21•(38-b); (x-9)•24; (y+4)•38.
11*(60+а)=11*60+11*а=660+11а 21*(38-b)=21*38-21*b=798-21b (х-9)*24=х*24-9*24=24х-216 (у+4)*38=у*38+4*38=38у+152