3x² - 2x + 17 > 0 Δ = ( -2 )² - 4 · 3 · 17 Δ = 4 - 204 Δ = - 200 Nie ma miejsc zerowych x ∈ R ================================================= -4x² + 10x ≤ 0 Δ = 10² - 4 · (-4) · 0 Δ = 100 √Δ = 10 x₁ = -10 - 10 ÷ -8 = -20 ÷ -8 = 2½ x₂ = -10 + 10 ÷ -8 = 0 ÷ -8 = 0 x ∈ ( -∞ ; 0 > u < 2½ ; ∞ ) ================================================= 28x² - 7 ≥ 0 Δ = 0 -4 · 28 · (-7) Δ = 784 √Δ = 28 x₁ = - 28 ÷ 56 = -½ x₂ = 28 ÷ 56 = ½ x ∈ ( -∞ ; -½ > u < ½ ; ∞ ) ================================================= -3(x-2)(4x+7) ≤ 0 -3(4x² + 7x -8x -14) ≤ 0 -12x² + 3x + 42 ≤ 0 Δ = 3² - 4 · (-12) · 42 Δ = 9 + 2016 = 2025 √Δ = 45 x₁ = -3 - 45 ÷ -24 = 2 x₂ = -3 + 45 ÷ - 24 = -1¾ x ∈ ( -∞ ; -1¾ > u < 2 ; ∞ ) ================================================= x² + x + ¼ > 0 Δ = 1 - 4 · 1 ·¼ Δ = 1 - 1 Δ = 0 x₁ = -1 ÷ 2 = -½ x ∈ ( -∞ ; -½ ) u ( -½ ; ∞ ) ================================================= -x² + 2x - 1 ≥ 0 Δ = 2² -4 · (-1) · (-1) Δ = 4 - 4 Δ = 0 x₁ = -2 ÷ -2 = 1 x ∈ ( -∞ ; 1 > u < 1 ; ∞ ) Jak coś to pisz na PW .
