(x + 3)³ ≥ 36(x + 3)
(x + 3)³ - 36(x + 3) ≥ 0
(x + 3)((x + 3)² - 36) ≥ 0
(x + 3)(x + 3 - 6)(x + 3 + 6) ≥ 0
(x + 3)(x - 3)(x + 9) ≥ 0
- + - +
________[- 9]_________[- 3]__________[3]__________
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Ответ : x ∈ [- 9 ; - 3] ∪ [3 ; + ∞)