Final answer:
Expressions a) and d) can be factored as (a + b)(a - b) and (a - b)(a² + ab + b²), respectively, while c) can be factored as (a + b)(a² - ab + b²). Expression b) is not factorizable using real numbers.
Step-by-step explanation:
The task is to factorize each given expression using the factoring by special products method. Here are the factorizations:
- a) a² − b² is a difference of squares and can be factored as (a + b)(a - b).
- b) a² + b² cannot be factored using real numbers as it does not represent a special product.
- c) a³ + b³ is a sum of cubes and can be factored as (a + b)(a² - ab + b²).
- d) a³ - b³ is a difference of cubes and can be factored as (a - b)(a² + ab + b²).