For this case we must factor the following expression:
[tex]16x ^ 2-25y ^ 2[/tex]
By definition, the formula of square difference states that:
[tex]a ^ 2-b ^ 2 = (a + b) (a-b)[/tex]
In this case:
[tex]a = 4x\\b = 5y[/tex]
Then, we can factor the expression as:
[tex](4x + 5y) (4x-5y)[/tex]
Answer:
[tex](4x + 5y) (4x-5y)[/tex]