Factor completely 49x² - 81. 
(7x + 9)², (7x - 9)², (7x + 9)(7x - 9), 7x - 9

Solution:

Given: Expression is 49x² - 81

In order to find roots, we need to factor the given polynomial.

⇒ 49x² - 81

⇒ ((7x)² - 9²)

This is in the form (a² - b²), we know that the difference of squares is (a² - b²) = (a + b)(a - b)

We can write ((7x)² - 9²) as (7x + 9) and (7x - 9)

⇒ (7x - 9)(7x + 9) = 0

Therefore, the factors of 49x² - 81 are(7x - 9)(7x + 9).

Factor completely 49x² - 81.

Summary:

Factors of 49x² - 81 are(7x - 9)(7x + 9).