Answer:
x ≤ a → x ∈ (-∞, a]
x < a → x ∈ (-∞, a)
x ≥ a → x ∈ [a, ∞)
x < a → x ∈ (a, ∞)
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Therefore:
x ≥ 7.8 → [7.8, ∞)
x < 7.8 → (-∞, 7.8)
x ≤ 7.8 → (-∞, 7.8]
x > 7.8 → (7.8, ∞)
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Step-by-step explanation: