(х-90)-705=1000
х-90=1000+705
х-90=1705
х=1705+90
х=1795
1800+(8000-у)=9000
8000-у=9000-1800
8000-у=7200
у=8000-7200
у=800
(х-90)-705=1000
х-90-705=1000
х-90=1000+705
х-90=1705
х=1705+90
х= 1795
1800+(8000-у)=9000
1800+8000-у=9000
8000-у=9000-1800
8000-у=7200
у=8000-7200
у=800
