Answer:
25x² - 16
Step-by-step explanation:
Given
(5x + 4)(5x - 4)
Each term in the second factor is multiplied by each term in the first factor, that is
5x(5x - 4) + 4(5x - 4) ← distribute parenthesis
= 25x² - 20x + 20x - 16 ← collect like terms
= 25x² - 16
