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