A rectangle has an area of 36 inches squared. Write an equation to show how the length (l) varies inversely the width (w).

What is the equation of the line?

Start with the first sentence, and the definition of the area of a rectangle:

l * w = 36

Rewrite the equation to get

l = 36 / w

or

w = 36 / l

Either one shows the inverse relationship between w and l.

Assuming the last part wants you to write an equation for an x-y graph, the equation would be

y = 36 / x