КВАДРАТНЫЕ УРАВНЕНИЯ 38б

х^2 + 7x + 12 = 0

x1 + x2 = -7        x1 = -4

x1 + x2 = 12       x2 = -3

9x^2 - 6x + 1 = 0

(3x - 1)^2 = 0

3x - 1 = 0

3x = 1

x = 1/3

-x^2 + 8x - 9 = 0

x^2 - 8x - 9 = 0

x1 + x2 = 8        x1 = -1

x1 + x2 = -9         x2 = 9

5x^2 - 8x + 3 = 0

D = 64 - 4*5*3 = 4

x1 = 8 - 2 / 10 = 0.6

x2 = 8 + 2 / 10 = 1

3x^2 + 7x - 6 = 0

D = 49 - 4*3*(-6) = 121

x1 = -7 - 11 / 6 = -3

x2 = -7 + 11 / 6 = 2/3

Объяснение: