Ta có 317 : n dư 23
=> 317 - 23 = 294
415 : n dư 37
=> 415 - 37 = 378
216 : n dư 6
=> 216 - 6 = 210
=> n \(\varepsilon\)ƯC(294,378, 210) n > 37
mà 294 = 2.3.72
378 = 2.33.7
210 = 2.3.5.7
ƯCLN( 294, 378, 210) = 2.3.7 = 42
ƯC(294, 378, 210) =Ư(42)
ƯC(294.,378, 210)= { 1;2;3; 6;7;14;21;42}
vì n > 37 nên n = 42