[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=343\\
x=49
\end{cases}\implies 343=k49\implies \cfrac{343}{49}=k
\\\\\\
7=k\qquad therefore\qquad \boxed{y=7x}
\\\\\\
\textit{when x = 8, what is \underline{y}?}\qquad y=7(8)\implies y=56 [/tex]
