Answer:
A. 81 - 49y²
Step-by-step explanation:
The triangle that represent a difference of squares is A.
It is easily recognize by looking at the numbers , the number gives a perfect square and the variable y is also squared
That is 9² = 81 and 7² = 49 and
Also the sign in-between them must me a negative sign, when the expression consist of the above, then it gives a different of square.
81 - 49y²
9² - 7²y²
(9 - 7y)(9 +7y)
Lets open back the parenthesis to check our answer
(9 - 7y)(9 +7y)
9(9+7y) -7y(9+7y)
81 +63y -63y -49y²
81 - 49y²
