Уровнения: 16+48:z =40
                   320:(52-х) =8
                   50 х у-72 =78                       

16+48:z=40 48:z=40-16 48:z=24 z=48:24 z=2 320:(52-х) =8, 52-х=320:8, 52-х=40, х=52-40, х=12 50*у-72=7850*у=78+7250*у=150у=150:50у=3