`x^7 + x^5 + x^4 + x^3 + x^2 + 1`
` = (x^7 - x^6 + 2x^5 - x^4 + 2x^3 - x^2 + x) + (x^6 - x^5 + 2x^4 - x^3 + 2x^2 - x + 1)`
` = x (x^6 - x^5 + 2x^4 - x^3 + 2x^2 - x + 1) + (x^6 - x^5 + 2x^4 - x^3 + 2x^2 - x + 1)`
` = (x+1)(x^6 - x^5 + 2x^4 - x^3 + 2x^2 - x + 1)`
``
`x^5 - x^4 - x^3 - x^2 - x -2`
`= (x^5 + x^4 + x^3 + x^2 + x) - (2x^4 + 2x^3 + 2x^2 + 2x + 2)`
` = x(x^4 + x^3 + x^2 + x + 1) - 2 (x^4 + x^3 + x^2 + x + 1)`
`= (x-2) (x^4 + x^3 + x^2 + x +1)`