Answer :

Sure! Let's explore and simplify the expression step-by-step:

The expression given is:

[tex]\[ x^4 - 9x^2 - 9x^2 + 81 \][/tex]

1. Combine Like Terms: Notice that the expression has two similar terms [tex]\(-9x^2\)[/tex] and [tex]\(-9x^2\)[/tex]. We can combine these two terms:

[tex]\[ -9x^2 - 9x^2 = -18x^2 \][/tex]

So, the expression becomes:

[tex]\[ x^4 - 18x^2 + 81 \][/tex]

2. Check for Further Simplification: In this case, we have combined all like terms and no further simplification of the expression [tex]\(x^4 - 18x^2 + 81\)[/tex] is necessary without specific instructions or additional context involving factorization.

This is the simplified form of the original expression, [tex]\( x^4 - 9x^2 - 9x^2 + 81 \)[/tex].