The variables x and y vary directly. Use the given values to write an equation that relates x and y: x = 4, y = - 16

Vary Directly: y = k*x

Vary Inversely: y = k/x

Because x and y vary directly, our equation will look like the first one.

y = k*x

With the inputted values:

-16 = k * 4

Now, to find k, isolate the variable

k = - 16/4 = - 4

Your final equation will then look like this:

y = - 4 * x