Ответ:

  1. \(4a^2b-3ab^2-a^2b+2ab^2=3a^2b-ab^2\).
  2. \(y^2-3y+3y-2y^2-4+2y^2=y^2-4\).
  3. \(2x^2-(2x^2-5xy)-(2xy-y^2)=3xy+y^2\).
  4. \(21m^2+14mn-21mn+6m^2=27m^2-7mn\).
  5. \(10p^2-10pq-8pq+8q^2=10p^2-18pq+8q^2\).
  6. \(a^4-5a^3b+3a^2b^2-2a^3b+10a^2b^2-6ab^3=a^4-7a^3b+13a^2b^2-6ab^3\).

Ответ: 1) \(3a^2b-ab^2\); 2) \(y^2-4\); 3) \(3xy+y^2\); 4) \(27m^2-7mn\); 5) \(10p^2-18pq+8q^2\); 6) \(a^4-7a^3b+13a^2b^2-6ab^3\).