Answer:
25x² - 1
Step-by-step explanation:
Given
(5x + 1)(5x - 1)
Each term in the second factor is multiplied by each term in the first factor, that is
5x(5x - 1) + 1(5x - 1) ← distribute both parenthesis
= 25x² - 5x + 5x - 1 ← collect like terms
= 25x² - 1
