已知n为大于100的自然数,若n3+100能被n+10整除,则满足条件的n的个数为_.
问题描述:
已知n为大于100的自然数,若n3+100能被n+10整除,则满足条件的n的个数为______.
答
(n3+100)÷(n+10)=
=n2−10n+100−
n3+100 n+10
.900 n+10
由题设,知n+10整除900.
整除900的数有900,450,300,225,180,150,100,90,75,60,…,1
即n+10=900,450,300,225,150,100,90,75,60,…,1.
∴n=890,440,290,215,140,90,…,-9.
又∵n>100(已知)
∴满足条件的n应是890,440,290,215,140,5个.
故答案为:5