Question

If y = 5.25 when x = 14, find the valueof k​

Answer 1

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

$y=kx \implies k=\dfrac{y}{x}=\dfrac{5.25}{14}=0.375$

If x and y are in inverse proportion, we have

$y=\dfrac{k}{x} \implies k=xy=5.25\cdot 14=73.5$