<span>- 5,6 × ( - 5,4 ) </span>÷ <span>( - 2,8 ) + 5,13 </span>÷ <span>( - 0,9 ) × ( - 3,15 ) = - 10,8 + 17,955 = 7,155</span>
10,2х-7,4х+0,88=2
2,8х=2-0,88
2,8х=1,12
х=1,12:2,8
х=0,4
(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
<span>у=800 </span>