Question

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

Answer 1

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