3x²-10x-8 5x²+6x+1 Решить через дискриминант.

1) 3x² - 10x - 8 = 0;

D = (-10)^2 - 4 * 3 * (-8) = 100 + 96 = 196;

x12 = (10 +- √196) / 2 * 6 = (10 +- 14) / 12;

x1 = (10 + 14) / 12 = 24 / 12 = 2; x2 = (10 - 14) / 12 = -4/12 = -1/3. 

2) 5x² + 6x + 1 = 0;

D = (6)^2 - 4 * 5 * 1 = 36 - 20 = 16;

x12 = (-6 +- √16) / 2 * 10 = (-6 +- 4) / 20;

x1 = (-6 - 4) / 20 = -10/20 = -1/2; x2 = (-6 + 4) / 20 = -2/20 = -1/10.