已知7^24-1可被40至50的两个数整除,这两个数是?
问题描述:
已知7^24-1可被40至50的两个数整除,这两个数是?
答
7^24-1
=(7^12+1)*(7^12-1)
=(7^12+1)*(7^6+1)(7^6-1)
=(7^12+1)*(7^6+1)(7^3+1)(7^3-1)
=(7^12+1)*(7^6+1)(7+1)(7^2-7+1)(7-1)(7^2+7+1)
=(7^12+1)*(7^6+1)*8*43*6*57
=(7^12+1)*(7^6+1)*48*43*57
所以这两个数是48和43
答
jarypan123,您好,首先说明一点,二楼的回答是错误的,应该是43与48,正否请听一下讲解,谢谢:
7^24-1=(7^12+1)(7^12-1)=(7^12+1)(7^6+1)(7^6-1)=…=(7^12+1)(7^6+1)(7^3+1)(7^3-1)= (7^12+1)(7^6+1)*(7+1)*(7^2-7+1)*(7-1)(7^2+7+1)= (7^12+1)(7^6+1)(7^3+1)*8*43*6*57
所以这两个数应为43和48
解答完毕,望笑纳
答
7^24-1
=(7^12+1)(7^12-1)
=(7^12+1)(7^6+1)(7^6-1)
=(7^12+1)(7^6+1)(7^3+1)(7^3-1)
=(7^12+1)(7^6+1)(7+1)(7^2-7+1)(7-1)(7^2+7+1)
∵7^2-7+1=43;(7+1)(7-1)=48
∴这两个数是43和48.
答
10和20啊,看出来的...可以带进去检验...是正确的