(x+3)(x²-3x+9)-x(x-3)(x+3)=(x³-27)-x(x²-9)=x³-27-x³+9x=9x-27=9(x-3).
при х=-5 ,получим 9(Х-3)=9(-5-3)=- 72,
(x+3)(x²-3x+9)-x(x-3)(x+3)=(x³-27)-x(x²-9)=x³-27-x³+9x=9x-27=9(x-3).
при х=-5 ,получим 9(Х-3)=9(-5-3)=- 72,