1) (4a)² - (-3b)² = 16a² - 9b²
2) 16m² - n¹⁶ = (4m)² - (n⁸)² = (4m - n⁸)(4m + n⁸)= (n⁸ + 4m)(4m - n⁸)
3) (5a⁵ + 2x)(2x - 5a⁵) = (2x + 5a⁵)(2x - 5a⁵) = (2x)² - (5a⁵)² = 4x² - 25a¹⁰
4) (1 - 2a)(1 + 2a + 4a²) = 1³ - (2a)³ = 1 - 8a³
5) 217² - 216² = (217 - 216)(217 + 216) = 1 * 433 = 433
6) 
