Question

What are the factors of x2 − 81? (x + 9)(x − 9) (x − 9)(x − 9) (x + 3)(x − 27) Prime

Answer 1

X^2-81=x^2-9^2=(x+9)(x-9)

this is the answer 

Answer 2

Answer: The correct option is (A) $(x+9)(x-9).$

Step-by-step explanation:  We are given to select the factors of the following quadratic expression :

$E=x^2-81~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)$

We will be using the following factorization formula :

$a^2-b^2=(a+b)(a-b).$

From (i), we have

$E\\\\=x^2-81\\\\=x^2-9^2\\\\=(x+9)(x-9).$

Thus, the factored form of the given expression is $(x+9)(x-9).$

Option (A) is CORRECT.