Question 7
There are some positive integer pairs $(x,y)$ that satisfy
$$\frac1{\sqrt{x}}+\frac1{\sqrt{y}}=\frac1{\sqrt{20}}.$$
How many different possible values of the product of $x$ and $y$ are there?
$$\frac1{\sqrt{x}}+\frac1{\sqrt{y}}=\frac1{\sqrt{20}}.$$
How many different possible values of the product of $x$ and $y$ are there?