1) 25b² + 10b + 1 = (5b)² + 2 * 5b * 1 + 1² = (5b + 1)²
2) 8ab + b² + 16a² = 16a² + 8ab + b² = (4a)² + 2 * 4a * b + b² = (4a + b)²
3) 25a² + 49 + 70a = 25a² + 70a + 49 = (5a)² + 2 * 5a * 7 + 7² = (5a + 7)²
4) 49a² + 28ab² + 4b⁴ = (7a)² + 2 * 7a * 2b² + (2b²)² = (7a + 2b²)²
5) a⁶ - 6a³b² + 9b⁴ = (a³)² - 2 * a³ * 3b² + (3b²)² = (a³ - 3b²)²
6) - 36m² + 60m - 25 = - (36m² - 60m + 25) = - ((6m)² - 2 * 6m * 5 + 5²) =
= - (6m - 5)²