Your question is quite incomplete: who's k?
Anyway, I'm assuming that this is one of those question about variation. If x and y are in proportion, we have
[tex]y=kx \implies k=\dfrac{y}{x}=\dfrac{5.25}{14}=0.375[/tex]
If x and y are in inverse proportion, we have
[tex]y=\dfrac{k}{x} \implies k=xy=5.25\cdot 14=73.5[/tex]