Question

设n为整数,使得(n^2-2n+4)是(n+3)的倍数,则满足这样条件的n值共有?个

Answer 1

n^2-2n+4

=(n+3)(n-5)+19

(n^2-2n+4)/(n+3)=n-5+19/(n+3)

n+3=±1

n+3=±19

解得：n=-4,-2,-22,16