请教2道数学题~~~纠结

Rainbeauty · 发表于 2011-4-12 21:24:38

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In the xy-coordinate plane, line m and line k intersect at the point (4, 3). Is the product of their slopes negative?
(1) The product of the x-intercepts of lines m and k is positive.
(2) The product of the y-intercepts of lines m and k is negative.
这个题选C的蛋似一点思路也木有。。。
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If the prime numbers p and t are the only prime factors of the integer m, is m a multiple of tp^2 ?
(1) m has more than 9 positive factors.
(2) m is a multiple of p^3.
选B 想不通诶。。。真的不知道它能被p^3整除跟是不是 tp^2的倍数有神马关系？p不能被t整除诶

renyu199014 · 发表于 2011-4-16 13:19:34

第一道题，你画一下图，直线m和k在x轴上的截距之积为正数，在y轴上的截距之积是负数，你就能发现这两条直线的斜率的符号是相反的。
第二道题，p和t是m的质因数，那么m=p^x*t^y,x和y是从0开始的正整数，现在B中说，m是p^3的倍数，也就是说m=t^a*p^3,那么，m肯定能被tb^2整除

请教2道数学题~~~纠结

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