x^4 - x^3 - x + 1; x^4 + x^3 - x^2 + x; 5x^3 - 5xy^2 + 25x^2 + 25xy; 3x^4 + 3x^2y^2 + 6x^3y - 27xx^2; 2x^5 - 6x^4 - 2a^x^3 - 6ax^3
x^4 - x^3 - x + 1
x^4 + x^3 - x^2 + x
5x^3 - 5xy^2 + 25x^2 + 25xy
3x^4 + 3x^2y^2 + 6x^3y - 27xx^2
2x^5 - 6x^4 - 2a^x^3 - 6ax^3
x^5 + x^4 + x^3 + x^2 + x + 1
x^3 - 1 + 5x^2 - 5 + 3x - 3