Відповіді §.13 - §.14 » §.13 (3)

Розв’яжіть систему нерівностей: 1. 16x2 ≥ 1, 3x < 9; 16x2 – 1 ≥ 0 x < 3 (4x – 1)(4x + 1) ≥ 0 x < 3 x ∈ (–∞; –1/4] ∪ [1/4; 3) 2. x2 < –15x x/7 + 2 ≤ 0|x7 x2 + 15x < 0 x + 14 ≤ 0 x = 0 x = –15 x ≤ –14 B. x ∈ (–15; –14] 3. x2 + x – 20 ≤ 0; x2 > 9; x1 = 4 (x – 3)(x + 3) > 0 x = 3 x = –3 x2 = –5 x ∈ [–5; –3) ∪ (3; 4] 4. x2 – 5x – 24 > 0 |x| ≤ 7 x1 = 8 x2 = –3 x ∈ (–∞; –3) ∪ (8; + ∞) x ∈ [–7; 7] x ∈ [–7; –3).