1)(x-a)(x-b)(x-c) 2)(x^2-1)(x^2+x+1)(x^2-x+1) 3)(x-y)(x^4+x^3y+x^2y^2+xy^3+y^4)

[latex](x-a)(x-b)(x-c)=(x^2-ax--bx+ab)(x-c)=\\ x^3-cx^2-bx^2+bcx-ax^2+acx+abx-abc[/latex] [latex](x^2-1)(x^2+x+1)(x^2-x+1)=(x^4+x^3-x-1)(x^2-x+1)=x^6-1 [/latex] [latex](x-y)(x^4+x^3y+x^2y^2+xy^3+y^4)=x^5-x^4y+x^4y-x^3y^2+x^3y^2-\\ -x^2y^3+x^2y^3-xy^4+xy^4-y^5=x^5-y^5[/latex]