Answer :

[tex]a^3\pm b^3=(a\pm b)(a^2\mp ab+b^2)[/tex]


[tex]y=x^3+64=x^3+4^3=(x+4)(x^2-4x+4^2)=(x+4)(x^2-4x+16)\\\\\\y=x^3-1000=x^3-10^3=(x-10)(x^2+10x+10^2)\\\\=(x-10)(x^2+10x+100)[/tex]