Let's simplify the expression:
x^4 - (x^2 - 1)(x^2 + 1)= x^4 - (x^4 + x^2 - x^2 - 1)= x^4 - x^4 - x^2 + x^2 + 1= 1
Therefore, the expression simplifies to 1.
Let's simplify the expression:
x^4 - (x^2 - 1)(x^2 + 1)
= x^4 - (x^4 + x^2 - x^2 - 1)
= x^4 - x^4 - x^2 + x^2 + 1
= 1
Therefore, the expression simplifies to 1.