Answer: The correct option is (A) [tex](x+9)(x-9).[/tex]
Step-by-step explanation: We are given to select the factors of the following quadratic expression :
[tex]E=x^2-81~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)[/tex]
We will be using the following factorization formula :
[tex]a^2-b^2=(a+b)(a-b).[/tex]
From (i), we have
[tex]E\\\\=x^2-81\\\\=x^2-9^2\\\\=(x+9)(x-9).[/tex]
Thus, the factored form of the given expression is [tex](x+9)(x-9).[/tex]
Option (A) is CORRECT.
