(-a+1/5)(-a-1/5)=________ (-a-5)(_________ )=25-a^2 100/99*101+1=________

题目

(-a+1/5)(-a-1/5)=________ (-a-5)(_________ )=25-a^2 100/99*101+1=________
1 (-a+1/5)(-a-1/5)=________
2 (-a-5)(_________ )=25-a^2
3 100/99*101+1=________
4 (x^4+1)(x^2+1)(x+1)(x-1)=____________

答案

1 (-a+1/5)(-a-1/5)=(-a)^2-(1/5)^2=a^2-1/25
2.(-a-5)(_a-5_ )=25-a^2
3 100/99*101+1=_100÷［(100-1)(100+1)+1］=100÷100^2=1/100.
4 (x^4+1)(x^2+1)(x+1)(x-1)
=(X^2+1)(X^2+1)(X^2-1)
=(X^4+1)(X^4-1)
=X^8-1.