Which expressions are differences of squares? Select each correct answer.


a^2−36

x^2+25

w^2−121

n^2−50



Which trinomials are perfect square trinomials?


Select each correct answer.


a^2+4a+16


a^2+15a+75


a^2+14a+49


a^2+26a+169




Factor completely.


4p² + 36p + 81


Note: Write the answer in the form: (ap+b)^2