（x-6)(x²+x+1)-x(2x+1)(3x-1)

（x-6)(x²+x+1)-x(2x+1)(3x-1)
（x-6)(x²+x+1)-x(2x+1)(3x-1)

（x-6)(x²+x+1)-x(2x+1)(3x-1)
-5*x^3-6*x^2-4*x-6

(x-6)(x^2十x十1)-x(2x十1)(3x-1)
=x(x^2十x十1)-6(x^2十x 1)-6x^3-x^2-x
=x^3十x^2十x-6x^2-6x-6-6x^3-x^2-x
=-5x^3-6x^2-6x-6