Ответ:

  1. а) \(8.1^2-8.1\cdot7.1=8.1(8.1-7.1)=8.1\cdot1=8.1\).
  2. б) \(3.8\cdot4.8-3.8^2=3.8(4.8-3.8)=3.8\cdot1=3.8\).
  3. в) \(7.2\cdot6.2-6.2^2=6.2(7.2-6.2)=6.2\cdot1=6.2\).
  4. г) \(5.9^2-5.9\cdot4.9=5.9(5.9-4.9)=5.9\cdot1=5.9\).