1. 3x2 - 10x +3

2. 5x2 – x - 42

3. 2х² + 3х – 5​

3*x^2 - 10*x + 3 = 0

d = 100 - 3 * 3 * 4 = 64

х1 = (10 - 8) / 6 = 1/3

x2 = (10 + 8) / 6 = 3

3*x^2 - 10*x + 3 = 3(x - 1/3)(x - 3)

x ^ 2 - 9 = (x - 3)(x + 3)

Сокращаем на х - 3, получаем (3x - 1)/(x + 3)

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

D = 1 + 4 * 4 * 5 = 81

x1 = (-1 + 9)/10 = 4/5 = 0.8

x2 = (-1 - 9)/10 = -1

5 * x ^ 2 + x - 4 = 5 * (x - 0.8)*(x + 1)

x^2 + x = x*(x+1)