Пошаговое объяснение:
1) 9-13x ≥0
9-13x = 100
-13x = 91
x = -7
2) x² + 12x+5 = -27
x²+12x + 32 = 0
D = 144 -128 = 16
x₁ = (-12-4)/2 = -8
x₂ = (-12+4)/2 = -4
3) 11-10x-x² ≥0
11-10x-x² = (x-1)²
-x² - 10x + 11 = x² - 2x +1
-2x² - 8x -+10 = 0
x²+4x - 5 = 0
x²+4x + 4 -9 = 0
(x+2)²-9 = 0
(x-1)(x+5) = 0
x₁ = 1 11-10-1 = 0 подходит
x₂ = -5 11 +50 -25 = 36 >0 подходит
Пошаговое объяснение:
1) 9-13x ≥0
9-13x = 100
-13x = 91
x = -7
2) x² + 12x+5 = -27
x²+12x + 32 = 0
D = 144 -128 = 16
x₁ = (-12-4)/2 = -8
x₂ = (-12+4)/2 = -4
3) 11-10x-x² ≥0
11-10x-x² = (x-1)²
-x² - 10x + 11 = x² - 2x +1
-2x² - 8x -+10 = 0
x²+4x - 5 = 0
x²+4x + 4 -9 = 0
(x+2)²-9 = 0
(x-1)(x+5) = 0
x₁ = 1 11-10-1 = 0 подходит
x₂ = -5 11 +50 -25 = 36 >0 подходит