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**Ragnarok** I am looking at a problem in a review of basic set notation which reads as follows:

*(a) [1, 5]*

(b) (1, 4)

(c) [-1, 6)

(d) [-4, 4]

The interval in (d) may be expressed in the form {x | x is a number and |x| ≤ 4}. Two of the other intervals listed can similarly be expressed with the aid of absolute values. Find the two and display the result.

I assume the intervals you could do this with would be (a) and (b), but I don't really know where to go from there. Could anyone offer any hints in the right direction? Thanks!