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 - 42 mn + 49n² - 9m(-4n) = 9m² - 42 mn + 49n² + 36mn = 9m² - 6 mn + 49n²
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 = 5b - 16
6)(12a-b)²-(9a-b)(16a+2b) = 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 = 4x + 13
9) (7a-5b)(7a+5b)-(4a+7b)² = 49a² - 25b² - 16a² - 56ab - 49b² = 33a² - 74b² - 56ab
10) (y-2)(y+3)-(y-1)²+(5-y)(y+5) = y² + y - 6 - y² + 2y - 1 +25 - y² = 3y + 18 - y²
42%=42:100=0,42
8%=8:100=0,08
7,25%=7,25:100=0,0725
568%=568:100=5,68