1)9с+9с=36.85-2.65
18с=34.2
с=34.2:18
с=1.9
2) 12=(7х-9)-(11-х)
12=7x-9-11+x
-7x-x=-11-12
-8x=-23
3) 8у-(7у-142)=51
8y-7y+142=51
8y-7y=51-142
1y=-91
y=-91
1)9с+9с=36.85-2.65
18с=34.2
с=34.2:18
с=1.9
2) 12=(7х-9)-(11-х)
12=7x-9-11+x
-7x-x=-11-12
-8x=-23
3) 8у-(7у-142)=51
8y-7y+142=51
8y-7y=51-142
1y=-91
y=-91