来自谭清成的问题
已知x2-5x-1991=0,求代数式(x−2)4+(x−1)2−1(x−1)(x−2)的值.
已知x2-5x-1991=0,求代数式(x−2)4+(x−1)2−1(x−1)(x−2)的值.
1回答
2020-11-18 03:49
已知x2-5x-1991=0,求代数式(x−2)4+(x−1)2−1(x−1)(x−2)的值.
已知x2-5x-1991=0,求代数式(x−2)4+(x−1)2−1(x−1)(x−2)的值.
∵x2-5x-1991=0,∴x2-5x=1991,∴(x−2)4+(x−1)2−1(x−1)(x−2)=(x−2)4+(x2−2x+1)−1(x−1)(x−2)=(x−2)4+(x2−2x)(x−1)(x−2)=(x−2)3+xx−1=x3−6x2+13x−8x−1=x3−x2−(5x2−13x+8)x−1=x2(x−1)−(5x−8...