Answer
$k=-4$
When $x=-0.3$, $y=1.2$
Work Step by Step
Since $y$ varies directly as $x,$ then the model equation is $y=kx.$ Using the given values, $
y=2 \text{ and }
x=-\dfrac{1}{2}
,$ then
\begin{align*}
y&=kx
\\\\
2&=k\left(-\dfrac{1}{2}\right)
\\\\
2&=-\dfrac{k}{2}
\\\\
-2(2)&=\left( -\dfrac{k}{2} \right)(-2)
\\\\
-4&=k
\end{align*}
With the value of $k$ above, the variation equation is $y=
-4
x.$ Substituting $x=-0.3,$ then the value of $y$ is
\begin{align*}
y&=-4(-0.3)
\\
y&=1.2
\end{align*}
