Ответ:

  1. \(68+x=95\)
    \(x=95-68=27\)
  2. \(y+214=305\)
    \(y=305-214=91\)
  3. \(647-y=258\)
    \(y=647-258=389\)
  4. \(x-3687=1788\)
    \(x=1788+3687=5475\)

Ответ: 1) \(x=27\); 2) \(y=91\); 3) \(y=389\); 4) \(x=5475\).