请教两道PREP数学题

imbalancey

1.       D是X,Y,Z方差，问X+5,Y+5,Z+5的方差是多少？

2.      5是n的乘数，n=p^2q,   p,q都是质数，问哪个一定是25的乘数，有p^2,q^2,pq,p^3q,p^2q^2这些

PERP上的题，不知道怎么做，求指教

trtwarrior

2. n has a factor of 5, so p could be 5 and q could be 5. If p is

5, p^2 has a factor of 25. If q is 5, q^2 has a factor of 25.

Combined together, p^2q^2 must have a factor of 25.

imbalancey

明白了，谢谢