5 х квадрате-7 х+2=0; 2 х квадрате-7 х+3=0; 3 х квадрате+2 х-5=0; 2 х квадрате-5 х+3=0; х квадрате + 3 х+1=0

1. 5x^2 - 7x + 2 = 0.

а) ищем D = 49 - 4 * 5 * 2 = 49 - 40 = 9

b) x1 = (7 + 3) / 10 = 1

x2 = (7 - 3) / 10 = 2/5

2. 2x^2 - 7x + 3 = 0.

а) ищем D = 49 - 4 * 2 * 3 = 49 - 24 = 25

b) x1 = (7 + 5) / 4 = 3

x2 = (7 - 5) / 4 = 1/2

3. 3x^2 + 2x - 5 = 0.

а) ищем D = 4 - 4 * 3 * (-5) = 4 + 60 = 64

b) x1 = (-2 - 8) / 6 = - 5/3

x2 = (-2 + 8) / 6 = 1

4. 2x^2 - 5x + 3 = 0.

а) ищем D = 25 - 4 * 2 * 3 = 25 - 24 = 1

b) x1 = (5 + 1) / 4 = 3/2

x2 = (5 - 1) / 4 = 1

5. x^2 + 3x + 1 = 0.

а) ищем D = 9 - 4 * 1 * 1 = 5

b) x1 = (-3 + √5) / 2

x2 = (-3 - √5) / 2