а)25у-у³=y(25-y²)=y(5-y)(5+y)
б) -4х²+8ху-4у²=-4(x²-2xy+y²)=-4(x-y)²
1) 25y-y^3=y(25-y^2)=y(5^2-y^2)=y(5-y)(5+y)
2) -4x^2+8xy-4y^2=-4(x^2-2xy+y^2)=-4(x-y)^2
