Решите через дискриминант

1) 4x^2-x-14=0

2) 3x^2-8x+5=0

3) 7x^2+x-8=0

D=b²-4ac

х1,2 = (-b+-√D) / (2 а)

1. D=1-4*4 * (-14) = √225=15

х1 = (1+15) / (2*4) = 16/8=2

х2 = (1-15) / (2*4) = (-14) / 8 = (-7) / 4

2. D=64-4*3*5=√4=2

х1 = (8+2) / (2*3) = 10/6=5/3

х2 (8-2) / (2*3) = 6/6=1

3. D=1-4*7 * (-8) = √225=5

х1 = (-1+5) / (2*7) = 4/14=2/7

х2 = (-1-5) / (2*7) = (-6) / 14 = (-3) / 7