Factorize
(x + y) ^ 2 - (y - 9) ^ 2

Answ er:

( x +  2 y  −  9  ) ( x  +  9 )

Step-by-step explanation:

Since both terms are perfect squares, factor using the difference of squares formula,  

a ^2  −  b ^2 =  ( a + b )  ( a − b )  where  a  =  x  +  y  and  b  =  y  −  9 .

( x +  2 y  −  9  ) ( x  +  9 )