Question

PLEASE HELP ASAP!!

Answer 1

By definition we have to:
 Difference of squares of two terms is equal to the product of the sum of these terms by the difference of these terms:
 $a ^ 2 - b ^ 2 = (a + b) (a - b)$
 We then have the following expression:
 $y^ 2-225$
 Rewriting we have:
 $y^ 2-15 ^ 2$
 Using the definition, we have to:
 $y ^ 2-15 ^ 2 = (y-15) * (y + 15)$
 Answer:
 B: is a difference of squares: (y-15)(y+15)