Ответ:

  1. \((2a+b)^2=4a^2+4ab+b^2\);
  2. \((0.2x-y)^2=0.04x^2-0.4xy+y^2\);
  3. \((5a-3x)^3=125a^3-225a^2x+135ax^2-27x^3\);
  4. \(\left(\frac12m+2n\right)^3=\frac18m^3+\frac32m^2n+6mn^2+8n^3\);
  5. \((3ab-x)(3ab+x)=9a^2b^2-x^2\);
  6. \((-x-2y)(-x+2y)=x^2-4y^2\);
  7. \((0.2p+q)(q-0.2p)=q^2-0.04p^2\);
  8. \((3-a)(9+3a+a^2)=27-a^3\);
  9. \((2x+3y)(4x^2-6xy+9y^2)=8x^3+27y^3\).