:::::::::::::::::::::::::
68,37-y=8,2•6,15
68,37-y=50,43
y=68,37-50,43
y=17,94
-4a(c+3d)-2b(c+3d)+(c+3d)=(-4a-2b+1)(c+3d)
7 7/30-(5 11/30-у)=3 19/30
7 7/30-5 11/30+у=3 19/30
у=3 19/30+5 11/30-7 7/30
у=1 23/30
(х-1 9/17)+2 14/17=5 5/17
х=5 5/17+1 9/17-2 14/17
х=4