The given expression is a perfect square trinomial.
Here we have the expression:
[tex](x^2 - 16)^2[/tex]
Notice that we can rewrite it as:
[tex](x^2 - 4^2)^2[/tex]
Then we can see that inside the parenthesis we have a difference of squares, but it is squared, so if we define:
[tex]x^2 = a\\4^2 = b[/tex]
We will have:
[tex](a - b)^2 = a^2 + -2ab + b^2 = (x^2)^2 - 2*(4^2)*(x^2) + (4^2)^2[/tex]
Which is in fact, a perfect square trinomial.
If you want to learn more about perfect squares:
https://brainly.com/question/1538726
#SPJ1