Question

What are the factors of x^2 - 81

(X + 9)(x -9)
(x-9)(x -9)
(x + 3)(x - 27)
Prime

Answer 1

(x-9)(x+9)

x^2-81

Write the number in exponential form with an exponent of 2

x^2-9^2

Use a^2-b^2=(a-b)(a+b)
(x-9)(x+9)

Answer 2

A. x-9 and x+9 because these are perfect squares. 9 times -9 is -81. x times x is x^2. 9 + -9 is 0