Answer
\begin{align*}
\text{$y$ varies directly with $x$}
\\
\text{constant of variation: }
\dfrac{7}{4}
\end{align*}
Work Step by Step
Using the properties of equality, the given equation, $
4y-7x=0
,$ is equivalent to
\begin{align*}
4y&=7x
\\\\
\dfrac{4y}{4}&=\dfrac{7x}{4}
\\\\
y&=\dfrac{7}{4}x
\end{align*}
Since the equation above takes the form of $y=kx$ or the direct variation model where $k$ is the constant of variation, then
\begin{align*}
\text{$y$ varies directly with $x$}
\\
\text{constant of variation: }
\dfrac{7}{4}
\end{align*}
