The problem asks to factor the expression $25x^2 - 16y^2$.

1. Problem Description

The problem asks to factor the expression $25x^2 - 16y^2$.

2. Solution Steps

The given expression is a difference of squares.

We can use the formula:

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

In this case, $a^2 = 25x^2$ and $b^2 = 16y^2$.

So, $a = \sqrt{25x^2} = 5x$ and $b = \sqrt{16y^2} = 4y$.

Therefore, $25x^2 - 16y^2 = (5x - 4y)(5x + 4y)$.

3. Final Answer

$(5x - 4y)(5x + 4y)$