Question

What is the interval notation for the compound inequality? x≤−4 or x≥5

(−∞, −4) or (5, ∞)
(−∞, −4] or [5, ∞)
(−4,5)
[−4,5]

Answer 1

(-∞, -4] or [5, ∞)

Explanation:

Because the solutions for x can also be equal to -4 and 5, brackets are used.

And because the solutions for x can be any number less than -4 or any number greater than 5, -∞ and ∞ are used respectively.