How to factor difference of squares

see explanation

Step-by-step explanation:

a² - b² ← is a difference of squares and factors as

= (a - b) (a + b)

Given

9x² - 16 ← a difference of squares

= (3x) ² - 4² → with a = 3x and b = 4

= (3x - 4) (3x + 4)

When an expression can be viewed as the difference of two perfect squares, i. e. a²-b², then we can factor it as (a+b) (a-b). For example, x²-25 can be factored as (x+5) (x-5). This method is based on the pattern (a+b) (a-b) = a²-b², which can be verified by expanding the parentheses in (a+b) (a-b).