Answer:
x² - 6x + 9
Explanation:
(x - 3)²
= (x - 3)(x - 3)
Each term in the second factor is multiplied by each term in the first factor
= x(x - 3) - 3(x - 3) ← distribute both parenthesis
= x² - 3x - 3x + 9 ← collect like terms
= x² - 6x + 9 ← in standard form