the line is increasing from left to right, meaning is higher on the right-end, therefore is an increasing slope, and "y varies directly proportional with x".
now, we know that when x = 4, y = 1, notice the big dot at (4,1), therefore,
[tex]\bf \qquad \qquad \textit{direct proportional variation}
\\\\
\textit{\underline{y} varies directly with \underline{x}}\qquad \qquad y=kx\impliedby
\begin{array}{llll}
k=constant\ of\\
\qquad variation
\end{array}\\\\
-------------------------------\\\\
\begin{cases}
x=4\\
y=1
\end{cases}\implies 1=k4\implies \cfrac{1}{4}=k\qquad \boxed{y=\cfrac{1}{4}x}[/tex]
