Решить уравнение: 1.(x^2 – 4x) + x – 4 = 0 2.x^2 + 3x – 28 = 0

Question

Решить уравнение:
1.(x^2 – 4x) + x – 4 = 0
2.x^2 + 3x – 28 = 0

Answer 1

Х^2 - 4x + x - 4 = 0
x^2 - 3x - 4 = 0
D = 9 - 4 * (-4) = 9 + 16 = 25     √D = 5
x1 = (3 + 5)/2 = 4
x2 = (3 - 5)/2 = -1
-----------------------------------
x^2 + 3x - 28 = 0
D = 9 - 4 * (-28) = 9 + 112 = 121     √D = 11
x1 = (-3 + 11)/2 = 4
x2 = (-3 -11)/2 = - 7