问题
选择题
若324-1可以被20到30之间的某两数整除,则这两个数是( )
A.24,26
B.25,27
C.26,28
D.27,29
答案
∵324-1=(312-1)(312+1)
=(36+1)(36-1)(312+1)
=(33-1)(33+1)(36+1)(312+1)
=26×28(36+1)(312+1),
则324-1可以被26与28整除.
故选C
若324-1可以被20到30之间的某两数整除,则这两个数是( )
A.24,26
B.25,27
C.26,28
D.27,29
∵324-1=(312-1)(312+1)
=(36+1)(36-1)(312+1)
=(33-1)(33+1)(36+1)(312+1)
=26×28(36+1)(312+1),
则324-1可以被26与28整除.
故选C