Answer:
This is an inverse variation, and the constant of variation is k = 2.
Step-by-step explanation:
Direct variation is something like:
y = k*x
Where k is the constant of variation.
So as x increases also increases y.
Inverse variation is something like:
y = k/x
k is the constant of variation.
In this case, if x increases, y decreases.
Now let's look at the equation:
-10 + 15*x*y = 20
Let's isolate y in one side of the equation:
15*x*y = 20 + 10 = 30
15*x*y = 30
y = 30/(15*x) = (30/15)/x = 2/x
y = 2/x
Then we can conclude that this is an inverse variation, with a constant of variation equal to 2.
