(13.4-y)-4.3-20.05=78.05+6.7
(13.4-y)=78.05+6.7+4.3+20.05
13.4-y=109,1
-у=109,1-13.4
у=-95,7
-57.62+4.3у-20.05-78.05-6.7=0
-162.42+4.3у=0
4.3у=162.42
у=