16x^2-25y^2 is equivalent to
16x² - 25y²16x² + 20xy - 20xy - 25y²4x(4x) + 4x(5y) - 5y(4x) - 5y(5y)4x(4x + 5y) - 5y(4x + 5y)(4x - 5y)(4x + 5y)