Explanation:
Direct variation means that the relation between the two variables is:
[tex]y=kx[/tex]
k is called constant of proportionality. To find it we have to replace a pair of values x and y and then solve for k. We're given y = -8 and x = 20:
[tex]\begin{gathered} -8=k\cdot20 \\ k=\frac{-8}{20}=-\frac{2}{5} \end{gathered}[/tex]
Therefore the relation is:
[tex]y=-\frac{2}{5}x[/tex]
Now, if we replace x = -4:
[tex]y=-\frac{2}{5}\cdot(-4)=\frac{2\cdot4}{5}=\frac{8}{5}[/tex]
Answer:
[tex]y=\frac{8}{5}[/tex]
