1) 5 (2x-3) - (8x-7) = 11-2x 2) 12x в квадрате + 17x-14=0

Найдем корни.

1) 5 * (2 * x - 3) - (8 * x - 7) = 11 - 2 * x;

Скобки раскроем.

5 * 2 * x - 5 * 3 - 8 * x + 7 = 11 - 2 * x;

10 * x - 15 - 8 * x + 7 = 11 - 2 * x;

Приведем подобные одночлены.

(10 * x - 8 * x) + (7 - 15) = 11 - 2 * x;

2 * x - 8 = 11 - 2 * x;

2 * x + 2 * x = 11 + 8;

4 * x = 19;

x = 19/4;

x = 16/4 + ¾;

x = 4 ¾.

2) 12 * x^2 + 17 * x - 14 = 0;

D = 17^2 - 4 * 12 * (-14) = 17 * 17 + 48 * 14 = 289 + 672 = 961 = 31^2;

x1 = (-17 + 31) * (2 * 12) = (20 - 6) / 24 = 14/24 = 7/12;

x2 = (-17 - 31) / (2 * 12) = - 48/24 = - 2.