1 K=1或-1/3
X^2＋2KX－3K^2=(X-1)X+(2K+1)X－3K^2能被X-1整除,
所以,2K+1=3K^2 解得~
2C
7^24－1=(7^12+1 )(7^6+1)(7^3+1)(7^3－1)
=(7^12+1 )(7^6+1)(7+1)(7^2+1-7)(7-1)(7^2+1+7)
=(7^12+1 )(7^6+1)*8*43*6*57
=(7^12+1 )(7^6+1)*48*43*57
3B
a^2