Simplify the equation x-y=0.
[tex]\begin{gathered} x-y=0 \\ x=y \\ x=(1)y \end{gathered}[/tex]
The general equation for proportional relationship is,
[tex]y=kx[/tex]
Where, k is constant of proportionality.
So equation y=(1)x is a proportional relation, with k=1.
So correct answer is,
x and y are proportional with k=1.
