Given that y is directly proportional to x.
So it can be written as,
[tex]y\propto x[/tex]or,
[tex]y=kx[/tex]where, k is the proprtinality constant.
[tex]\begin{gathered} k=\frac{y}{x} \\ k=\frac{35}{7} \\ k=5 \end{gathered}[/tex]Hence, constant of proportioanlity is 5.
