ANSWER
• (x+a)(x-a) = x² - a²
,• (x+a)² = x² + 2ax + a²
,• (x-a)² = x² - 2ax + a²
EXPLANATION
For the first product we can use the difference of two squares rule:
[tex]a^2-b^2=(a+b)(a-b)[/tex]Then, for the other two we just have to apply the perfect square rule:
[tex](a\pm b)^2=a^2\pm2ab+b^2[/tex]