#### Answer

$k=\frac{4}{3}$;
When $x=-3$, $y=-4$

#### Work Step by Step

Write the formula for direct variation, which is $y=kx.$
Then, write the formula for the constant of variation, which is $k=\frac{y}{x}$.
Substitute the given values ti solve for the constant of variation, which yields $k=\frac{4}{3}$.
Use the direct variation formula to solve for $y$ when $x=-3$:
$y=kx
\\y=\frac{4}{3}(-3)
\\y=-4$.