Answer:
x² - 16xy + 64y²
Step-by-step explanation:
The difference of x and 8y is x - 8y
The square of the difference is (x - 8y)² = (x - 8y)(x - 8y)
Expand by multiplying each term in the second factor by each term in the first factor, that is
x(x - 8y) - 8y(x - 8y) ← distribute both parenthesis
= x² - 8xy - 8xy + 64y² ← collect like terms
= x² - 16xy + 64y²
