Ответ:

a) x1 = 3, x2 = -2

б) x1 = 3, x2 = -5

в) x1 = 1, x2 = -0.5

Объяснение:

а) x² - |x| - 6 = 0

x² - x - 6 = 0

D = 1 + 24 = 25 > 0

x1 = (1 + 5) : 2 × 1 = 6 : 2 = 3

x2 = (1-5) : 2 × 1= -4 : 2 = -2

x1 = 3, x2 = -2

б) x² + 2lxl - 15 = 0

x² + 2x - 15 = 0

D = 4 + 60 = 64 > 0

x1 = (-2 + 8) : 2 = 6 : 2 = 3

x2 = (-2 - 8) : 2 = -10 : 2 = -5

x1= 3, x2 = -5

в) 2x² - lxl - 1 = 0

2x² - x - 1 = 0

D = 1 + 8 = 9

x1 = (1 + 3) : (2 × 2) = 4 : 4 = 1

x2 = (1 - 3) : (2 × 2) = -2 : 4 = -1/2 = -0.5

x1 = 1, x2 = -0.5