Answer:
(X + 9)(x -9)
Step-by-step explanation:
Subtraction of perfect squares:
The factors of a subtraction of perfect squares is given by:
[tex]a^2 - b^2 = (a-b)(a+b)[/tex]
What are the factors of x² - 81?
This can be written as:
[tex]x^2 - 81 = (x)^2 - (9)^2[/tex]
So
[tex](x)^2 - (9)^2 = (x - 9)(x+9)[/tex]
