<=> (x^4 - x^3) - (3x^3 - 3x^2) + (2x-2) =0 <=>x^3(x-1)-3x^2(x-1) + 2(x-1) =0
<=>(x-1)(x^3 - 3x^2 + 2) = 0 <=>(x-1) = 0 (1) hoac (x^3-3x^2 +2) =0 (2)
gai (1) <=> x-1 = 0 <=> x=1
giai (2) ta dk : x^3 - 3x^2 + 2 =0 <=> (x^3 - x^2) -(2x^2 - 2x) -(2x -2) =0
<=> x^2(x-1) -2x(x-1) -2(x-1) = 0 <=> (x-1)(x^2-2x-2) =0
<=> x-1 = 0 hoac x^2 - 2x -2=0
sau do ban giai tuong tu se tim ra ket qua