ответ: (x+2.3)-(x+7.8)=-11\2
-(7.2-y)+(-y+1.6)=5,6
-(y-7.4+x)-(11.6-y)=-5*x-21/5
(-2.6+x+y)-(x-y-2.6)=(-2.6+x+y)-(x-y-2.6)=(-2.6)+x+y-x+y+2.6=(-2.6)+2.6+x-x+y+y=2y
ответ: (x+2.3)-(x+7.8)=-11\2
-(7.2-y)+(-y+1.6)=5,6
-(y-7.4+x)-(11.6-y)=-5*x-21/5
(-2.6+x+y)-(x-y-2.6)=(-2.6+x+y)-(x-y-2.6)=(-2.6)+x+y-x+y+2.6=(-2.6)+2.6+x-x+y+y=2y