1) (x - 4)² - 6 = x² - 8x + 16 - 6 = x² - 8x + 10
2) 10a + (a - 5)² = 10a + a² - 10a + 25 = a² + 25
3) (3m - 7n)² - 9m(n - 5n) = 9m² - 42mn + 49n² - 9mn + 45mn = 9m² + 49n² - 6mn
4) (6a - 3b)² + (9a + 2b)² = 36a² - 36ab + 9b² + 81a² + 36ab + 4b² = 117a² + 13b²
5) b(b - 3) - (b - 4)² = b² - 3b - (b² - 8b + 16) = b² - 3b - b² + 8b - 16 = 5b - 16
6) (12a - b)² - (9a - b)(16a + 2b) = 144a² - 24ab + b² - (144a² + 18ab - 16ab - 2b²) = 144a² - 24ab + b² - 144a² - 2ab + 2b² = -26ab + 3b²
7) x(2x - 9)² - 2x(15 + x)² = x(4x² - 36x + 81) - 2x(225 + 30x + x²) = 4x³ - 36x² + 81x - 450x - 60x² - 2x³ = 2x³ - 96x² - 369x
8) (x + 2)² - (x - 3)(x + 3) = (x² + 4x + 4) - (x² - 9) = x² + 4x + 4 - x² + 9 = 4x + 13
9) (7a - 5b)(7a + 5b) - (4a + 7b)² = 49a² - 25b² - (16a² + 56ab + 49b²) = 49a² - 25b² - 16a² - 56ab - 49b² = 33a² - 74b² - 56ab
10) (y - 2)(y + 3) - (y - 1)² + (5 - y)(y + 5) = (y² + 3y - 2y - 6) - (y² - 2y + 1) + (25 - y²) = (y² + y - 6) - (y² - 2y + 1) + (25 - y²) = y² + y - 6 - y² + 2y - 1 + 25 - y² = -y² + 3y + 18