W(x)=x^4-16x^2=x^2(x^2-16)=x^2(x^2-4^2)=x^2(x-4)(x+4)
W(x)=x^3+8x^2+16x=x(x^2+8x+16)=x(x+4)^2=x(x+4)(x+4)
$W(x)=-x^3+6x^2-7x=-x(x^2-6x+7)=$cd niżej
równanie kwadratowe
x^2-6x+7=0
\Delta=b^2-4ac=(-6)^2-4*1*7=36-28=8
\sqrt{\Delta}=\sqrt{8}=\sqrt{2*4}=2\sqrt{2}
x_1=\frac{-b-\sqrt{\Delta}}{2a}=\frac{6-2\sqrt{2}}{2}=\frac{2(3-\sqrt{2})}{2}=3-\sqrt{2}
x_1=\frac{-b+\sqrt{\Delta}}{2a}=\frac{6+2\sqrt{2}}{2}=\frac{2(3+\sqrt{2})}{2}=3+\sqrt{2}
cd=-x(x-3-\sqrt{2})(x-3+\sqrt{2})