Given an instance of the STUDENTS relation as shown below:

For (StudentName, StudentAge) to be a key for this instance, the value $$X$$ should NOT be equal to ________.

The maximum number of superkeys for the relation schema $$R(E, F, G, H)$$ with $$E$$ as key is ______.

Let $$k = {2^n}.$$ A circuit is built by giving the output of an ݊$$n$$-bit binary counter as input to an $$n$$-to-$${2^n}$$ bit decoder. This circuit is equivalent to a

Consider the equation $${\left( {123} \right)_5} = {\left( {x8} \right)_y}$$ with $$x$$ and $$y$$ as unknown. The number of possible solutions is _________.