Помогите #627 и #629 Пожалуйста

627. 1) b² -2b+ 1 = (b-1)² 2) 4 + 4n+n² = (2 +n)² 3) x² -14x+49 = (x-7)² 4) 4a² + 4ab+ b² = (2a+b)² 5) 9x² - 24xy + 16y² = (3x-4y)² 6) a⁶- 2a³+1 = (a³-1)² 7) 36a⁶-84a³b⁵+49b¹⁰ = (6a³ - 7b⁵)² 8)  81x⁴y⁸ - 36x²y⁴z⁶ = (9x²y⁴ - 2z²)²  629 1) b²-30b+225 = (b- 15)² = (6-15)² = (-9)² = 81 2) 100a²+60ab+9b² = (10a+3b)² = (8-9)² = (-1)² = 1