2x^4 - 2x^3 - x^2 + 1
= 2x^3[x - 1] - [x^2 - 1]
= 2x^3(x - 1) - (x - 1)(x + 1)
= (x-1)[2x^3 - x - 1]
= (x-1)[2x^3 - 2x^2 + 2x^2 - 2x + x - 1]
= (x-1)[(x-1)(2x^2 + 2x + 1)]
= (x-1)^2[2x^2 + 2x + 1]
2x^4 - 2x^3 - x^2 + 1
= 2x^3[x - 1] - [x^2 - 1]
= 2x^3(x - 1) - (x - 1)(x + 1)
= (x-1)[2x^3 - x - 1]
= (x-1)[2x^3 - 2x^2 + 2x^2 - 2x + x - 1]
= (x-1)[(x-1)(2x^2 + 2x + 1)]
= (x-1)^2[2x^2 + 2x + 1]