How do we use inverse variation?

Aim: How do we use inverse variation?

Inverse Variation is a relationship between two variables x and y, where x varies inversely with y and their product is constant. In other words, when x increases, y decreases by the same factor to 
make sure the product remains the same. 

x*y=k  ( K is constant)

We can find K by multiplying x and y.

Example:

1. If x=4 and y=5, write an equation that describing this inverse variation?
Multiply x and y
4*5=20
xy=20 or y=20/x

2. Find y using inverse variation?

x	y
3	20
6	10
12	y

First, multiply 3 and 20 to find the constant product.
20*3=60
xy=60 (The product of x and y will always be 60)
Then, substitute 12 for x.
12y=60
Now, divide 12 from both side to get the y alone. 
12y=60
12    12
The answer is y=5.