The form of the equation of the direct proportional is
[tex]y=kx[/tex]
k is the constant of variation
We can find it from the initial values of x and y
Since at x = -2 y = 10, then
Substitute x by -2 and y by 10 to find k
[tex]\begin{gathered} x=-2,y=10 \\ 10=k(-2) \\ 10=-2k \end{gathered}[/tex]
Divide both sides by -2 to find k
[tex]\begin{gathered} \frac{10}{(-2)}=\frac{-2k}{(-2)} \\ -5=k \end{gathered}[/tex]
The value of k is -5
Then the equation is
[tex]y=-5x[/tex]
