To solve the question, we will follow the steps below:
[tex]f(x)=x^2-1[/tex]To find f(f(x)), we will simply replace x by x² - 1 in the function x² - 1
That is:
f((fx)) = (x²-1)² - 1
Then we open the parenthesis
f(f(x)) = (x² - 1)(x² -1) - 1
=x²(x²-1)-1(x²-1) - 1
= x⁴ - x² - x² + 1 - 1
= x⁴ - 2x²
So the correct option is option D. which is x⁴ - 2x²
