Determine whether the polynomial is a difference of squares and if it is, factor it. y2-225 a: is not a difference of squares b: is a difference of squares: (y-15)(y+15) c: is a different of squares (y-15)^2 d: is a difference of squares (y+15)^2 8th grade math

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:
 
 We then have the following expression:
 
 Rewriting we have:
 
 Using the definition, we have to:
 
 
 B: is a difference of squares: (y-15)(y+15)