Page 80 - Numbertheory
P. 80
@ @Hßìÿa@ö§aI@†a‡Èÿa@óî‹Åä@@
:
(n + 3) | (n 2 + 7) (n + 3) | (n 2 + 3n )
. (n + 3) |16 . (n + 3) | (3n + 9) . (n + 3) | (3n − 7)
. n = 13 n = 5 n = 1
9 6a3 + 2b 5 [Aust.MC 1982] ( )
17 ( ) ba 9( ) 2 ()
11 ( )
6a3 + 2b5 = 600 +10a + 3 + 200 +10b + 5 :( )
= 9(89 + a + b ) + (a + b + 7)
a+b +7 . 0 ≤ a +b ≤18 0 ≤ b ≤ 9 0 ≤ a ≤ 9
. a + b = 11 a +b = 2 9
. 11
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