Найдите корешки трехчлена.1) 12х^2-4х-5.2)5х^2+9х-2.3)4х^2-64

1) 12x - 4x - 5 = 0

a = 12, b = - 4, c = - 5,

D = b - 4ac = (- 4) - 4 * 12 * (- 5) = 16 + 240 = 256 gt; 0 - 2 реальных корня,

x₁ = (- b + D) / 2a = (4 + 16) / 24 = 5/6,

x₂ = (- b - D) / 2a = (4 - 16) / 24 = - 1/2.

2) 5x + 9x - 2 = 0

a = 5, b = 9, c = - 2,

D = b - 4ac = 9 - 4 * 5 * (- 2) = 81 + 40 = 121 gt; 0 - 2 действительных корня,

x₁ = (- b + D) / 2a = (- 9 + 11) / 10 = 1/5,

x₂ = (- b - D) / 2a = (- 9 - 11) / 10 = - 2.

3) 4х - 64 = 0,

4х = 64,

х = 64 : 4,

х = 16,

x₁ = 4;

x₂ = - 4.