If a,b and c are unit vectors, then the maximum value of `|a-b|^(2)+|b-c|^(2)+|c-a|^(2)` is?

If a, b and c are unit vectors satisfying |a-b|^(2)+|b-c|^(2)+|c-a|^(2)=9 , then |2a+5b+5x| is

If a^(2)+b^(2)+c^(2)=1 where, a,b, cin R , then the maximum value of (4a-3b)^(2) + (5b-4c)^(2)+(3c-5a)^(2) is

If a,b,c are positive real numbers and 2a+b+3c=1 , then the maximum value of a^(4)b^(2)c^(2) is equal to

If a,b,c in R^(+) such that a+b+c=21 then the maximum value of a^(2)b^(3)c^(2) is equal to