Your answer is D) (5xy² - 1)(5xy² + 1)
This is because all of the terms in 25x²y^4 are square numbers, so that means we can write the expression as a difference of two squares. The + 1 and - 1 mean that the non-squared terms will cancel out:
√25 = 5, so we know the first coefficient is 5
√(x²) = x
√(y^4) = y²
This gives us 5xy², and this option is only available in part D.
You can check your answer by expanding and seeing that you get 25x²y^4 - 5xy² + 5xy² - 1.
I hope this helps! Let me know if you have any questions :)
