已知x^2-5x-1997=0,求代数式[(x-2)(x-2)-(x-1)(x-1)+1]/(x-2)的值...
问题描述:
已知x^2-5x-1997=0,求代数式[(x-2)(x-2)-(x-1)(x-1)+1]/(x-2)的值...
答
[(x-2)(x-2)-(x-1)(x-1)+1]/(x-2)
={[(x-2)+(x-1)][(x-2)-(x-1)]+1}/(x-2)
=[-(2x-3)+1]/(x-2)
=(4-2x)/(x-2)
=-2