Я не знаю как это решать
..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
В решении.
Объяснение:
а) 3в² - 48 = 3(в² = 16) = 3(в - 4)(в + 4);
б) 19х² - 19у² = 19(х² - у²) = 19(х - у)(х + у);
в) 18х² + 12х + 2 = 2(9х² + 6х + 1) = 2(3х + 1)² = 2(3х + 1)(3х + 1);
1) 10а + 15с = 5(2а + 3с);
2) 4a² - 9b² = (2a - 3b)(2a + 3b);
3) 6xy + ab - 2bx - 3ay =
= (6xy - 3ay) - (2bx - ab) =
= 3y(2x - a) - b(2x - a) =
= (2x - a)(3y - b);
4) 4a² + 28ab + 49b² = (2a + 7b)² = (2a + 7)(2a + 7);
5) b(a + c) + 2a + 2c =
= b(a + c) + (2a + 2c) =
= b(a + c) + 2(a + c) =
= (a + c)(b + 2);
6) 5a³c - 20acb - 10ac = 5ac(a² - 4b - 2);
7) x² - 3x - 5x + 15 =
= x² - 8x + 15;
Приравнять к нулю и решить как квадратное уравнение:
x² - 8x + 15 = 0
D=b²-4ac =64 - 60 = 4 √D=2
х₁=(-b-√D)/2a
х₁=(8-2)/2
х₁=6/2
х₁=3;
х₂=(-b+√D)/2a
х₂=(8+2)/2
х₂=10/2
х₂=5.
Разложение:
x² - 8x + 15 = (х - 3)(х - 5);
8) 9а² - 6ас + с² = (3а - с)² = (3а - с)(3а - с).
..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................