Question

已知代数式x(x+2)(x-2)-(x-3)(x^2+3x+9)

Answer 1

x(x+2)(x-2)-(x-3)(x^2+3x+9)

=x(x^2-4)-(x^3-3^3)

=x^3-4x-x^3+27

=-4x+27

x=-1/4

x(x+2)(x-2)-(x-3)(x^2+3x+9)=-4*(-1／4)+27=1+27=28

x(x+2)(x-2)-(x-3)(x^2+3x+9)=7

-4x+27=7

4x=20

x=5

x(x+2)(x-2)-(x-3)(x^2+3x+9)27/4