The correct answer is option A. 81 - 49y².
What are different squares?
It exists easily identified by looking at the numbers, the number shows a perfect square, and the variable y exists also squared
That is 9² = 81 and 7² = 49
Also, the sign in-between them must be a negative sign, when the expression consists of the above, then it provides a different square.
81 - 49y²
9² - 7²y²
(9 - 7y)(9 +7y)
Opening back the parenthesis to verify our answer
(9 - 7y)(9 +7y)
9(9+7y) -7y(9+7y)
81 +63y -63y -49y²
81 - 49y²
Therefore, the correct answer is option A. 81 - 49y².
To learn more about the different squares
https://brainly.com/question/15975147
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