[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} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ (-3,2)~~ \begin{cases} x=-3\\ y=2 \end{cases}\implies 2=k(-3)\implies -\cfrac{2}{3}=k[/tex]
