80. 7589-!-item-!-187;#058&005492 请教！！

halcyonline · 发表于 2008-10-12 16:38:00

想请教

80. 7589-!-item-!-187;#058&005492

If x and y are positive integers such that x = 8y + 12, what is the greatest common divisor of x and y ?

(1) x = 12u, where u is an integer.

(2) y = 12z, where z is an integer

答案选B

能请各位帮我解答一下吗

naonao7949 · 发表于 2008-10-12 17:12:00

同困惑，等待牛牛解答

naonao7949 · 发表于 2008-10-12 17:30:00

(1) x=12,20,28,36...60 对应的y=0,1,2,3,...6因为x=12u,所以x=12,36 60y=0,3,6 ==>最大公约数不同 (2)同理根据y=12Z, y=12,24,36,x=....最大公约数为2^2*3

群里牛牛的解答，共勉

halcyonline · 发表于 2008-10-22 23:07:00

多谢帮助：）

多谢！