[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}\\\\
-------------------------------[/tex]
[tex]\bf \textit{y varies jointly with s and the square of e}\qquad y=kse^2
\\\\\\
\textit{we also know that }
\begin{cases}
s=2\\
e=3\\
y=54
\end{cases}\implies 54=k(2)(3)^2
\\\\\\
54=18k\implies \cfrac{54}{18}=k\implies 3=k\qquad \qquad \boxed{y=3se^2}
\\\\\\
\textit{when s = 7 and e = 11, what is \underline{y}?}\qquad y=3(7)(11)^2[/tex]
