Thực hiện phép tính (x -1)(2x - 1)(3x - 1)

Ta có: x−12x−13x−1

                =2xx−1−1x−13x−1

                =2x2−2x−x+13x−1

                =2x2−3x+13x−1

                =2x23x−1−3x3x−1+13x−1

                =6x3−2x2−9x2+3x+3x−1=6x3−11x2+6x−1