The problem asks to expand the expression $(5x - 3y)(5x + 3y)$.

1. Problem Description

The problem asks to expand the expression $(5x - 3y)(5x + 3y)$.

2. Solution Steps

We can use the formula for the difference of squares:

$(a-b)(a+b) = a^2 - b^2$

In this case, we have $a = 5x$ and $b = 3y$. Therefore, we can apply the formula as follows:

$(5x - 3y)(5x + 3y) = (5x)^2 - (3y)^2$

Now, we simplify the terms:

$(5x)^2 = 5^2 x^2 = 25x^2$

$(3y)^2 = 3^2 y^2 = 9y^2$

Thus, we have:

$(5x - 3y)(5x + 3y) = 25x^2 - 9y^2$

3. Final Answer

$25x^2 - 9y^2$