it is given that x and y have inverse relation
so K = xy
put y = -4 and x = 1/2
[tex]\begin{gathered} k=\frac{1}{2}\times-4 \\ k=-2 \end{gathered}[/tex]now
y = 2
then'
[tex]\begin{gathered} -2=x\times2 \\ x=\frac{-2}{2} \\ x=-1 \end{gathered}[/tex]so the value of x = -1
[tex]\begin{gathered} x\infty\frac{1}{y} \\ x=\frac{K}{y} \\ K=xy \end{gathered}[/tex]