Respuesta :
[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}\\\\
-------------------------------\\\\
\textit{we also know that }
\begin{cases}
y=3\\
x=12
\end{cases}\implies 3=k12\implies \cfrac{3}{12}=k
\\\\\\
\cfrac{1}{4}=k\qquad therefore\qquad \boxed{y=\cfrac{1}{4}x}
\\\\\\
\textit{when x = 18, what is \underline{y}?}\qquad y=\cfrac{1}{4}(18)[/tex]
