What is the largest positive integer n for which n 3 + 1 0 0 is divisible by n + 1 0 ?
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Nice work! Nice solution +1 :)
We can apply synthetic division to n + 1 0 n 3 + 1 0 0 = n 2 − 1 0 n + 1 0 0 − n + 1 0 9 0 0 ;
n + 1 0 must be a factor of 9 0 0 ⟹ n = 8 9 0 . To see that we know that ( 9 0 0 ∣ 8 9 0 3 + 1 0 0 );
Thus, the greatest integer n for which n + 1 0 divides 9 0 0 is 8 9 0
Typo:It's n ² − 1 0 n + 1 0
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n + 1 0 n 3 + 1 0 0 = n + 1 0 ( n 3 + 1 0 0 0 ) − 9 0 0 = n + 1 0 n ³ + 1 0 0 0 − n + 1 0 9 0 0 = n ² − 1 0 n + 1 0 0 − n + 1 0 9 0 0 ⟹ n + 1 0 ∣ 9 0 0 The largest positive integer that divides 9 0 0 is 9 0 0 itself.Hence: ⟹ n + 1 0 = 9 0 0 ⟹ n = 8 9 0