Ответ:

  1. \((x+2,3)-(x+7,8)=x+2,3-x-7,8=-5,5\).
  2. \(-(7,2-y)+(-y+1,6)=-7,2+y-y+1,6=-5,6\).
  3. \(-(y-7,4+x)-(11,6-y)=-y+7,4-x-11,6+y=-x-4,2\).
  4. \((-2,6+x+y)-(x-y-2,6)=-2,6+x+y-x+y+2,6=2y\).