A)9a-3ax+ax^2-27-x^3=3a(3-x)+ax^2-x^3-27= 3a(3-x)+x^2(a-x)-27
б)2y^2-20y+50-2m^2=2y^2-2m^2+50-20y=2(y^2-m^2)+10(5-2y)
с)8x^3-y^3-4x^2+4xy-y^2=8x^3-4x^2+4xy-y^2-y^3=4x(2x^2-x+y)-y^2(y+1)
д)81a^8-16c^12+3a^2+2c^3=81a^8+3a^2+2c^3-16^12=3a^2(27+1)+2c^3(1-8c^9)