√336+√575−√189−√828=√21−√23
(x+2y^2)(x^2-2xy^2+4y^4)(x^6-8x^3y^6+64y12=((x+2y^2)(x2−2xy^2+4y^4))(x6+−8x^3y6+64y^12)=((x+2y^2)(x^2−2xy^2+4y^4))(x^6)+((x+2y^2)(x^2−2xy^2+4y^4))(−8x^3y^6)+((x+2y^2)(x^2−2xy^2+4y^4))(64y^12)=8x^6y^6+x^9−64x^3y^12−8x^6y^6+512y^18+64x^3y^12=512y^18+x^9