1) 9х^2+6x-8=0 2) 25x^2-10x-3=0 3) x^2-5x+4=0 4) x^2-3x-10=0 5) 2x^2+3x-5=0 6) 5x^2-7x-6=0

Решаем квадратные уравнения:

1) 9 * х^2 + 6 * x - 8 = 0;

D = 6 * 6 - 4 * (-8) * 9 = 36 + 288 = 324;

х1 = (-6 + 18)/18 = 12/18 = 2/3;

х2 = (-6 - 18)/18 = -24/18 = -4/3;

2) 25 * x^2 - 10 * x - 3 = 0;

D = 10 * 10 - 4 * (-3) * 25 = 100 + 300 = 400;

х1 = (10 + 20)/50 = 3/5;

х2 = (10 - 20)/50 = -1/5;

3) x^2 - 5 * x + 4 = 0;

D = 25 - 16 = 9;

х1 = (5 + 3)/2 = 4;

х2 = (5 - 3)/2 = 1;

4) x^2 - 3 * x - 10 = 0;

D = 9 + 40 = 49;

х1 = (3 + 7)/2 = 5;

х2 = (3 - 7)/2 = -2;

5) 2 * x^2 + 3 * x - 5 = 0;

D = 9 + 40 = 49;

х1 = (-3 + 7)/4 = 1;

х2 = (-3 - 7)/4 = -5/2;

6) 5 * x^2 - 7 * x - 6 = 0;

D = 49 + 120 = 169;

х1 = (7 + 13)/10 = 2;

х2 = (7 - 13)/10 = -3/5.