You can
put this solution on YOUR website! .
In mathematics, a normed vector space is a vector space over the real or complex numbers, on which a norm is defined.
A norm is the formalization and the generalization to real vector spaces of the intuitive notion of distance in the real world.
For details, see this Wikipedia article
https://en.wikipedia.org/wiki/Normed_vector_space
or look into YOUR textbook.