What are the intervals on the number line for | x + 5 | ≥ 2?

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In summary, an interval on a number line is a set of numbers represented by a line segment, including all the numbers between two given points, and can be written in the form of [a, b] with square brackets indicating the inclusion of endpoints. There is a difference between open intervals (not including endpoints) and closed intervals (including endpoints), and intervals can also be infinite, represented by the infinity symbol (∞). In mathematics, intervals are commonly used to represent ranges of numbers, in inequalities, graphs, and in calculus to determine limits and continuity.
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mathdad
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The set of real numbers satisfying the given inequality is one or more intervals on the number line. Show each interval on the number line.

1. | x - 1 | < or = 1/2

Solution:

-1/2 < or = x - 1 < or = 1/2

(-1/2) + 1 < or = x < or = (1/2) + 1

1/2 < or = x < or = 3/2

----[1/2-------3/2]----

Correct?

2. | x + 5 | ≥ 2

Solution:

This question says that x is at least two units away from 5 on the number line.

x + 5 ≥ 2

x ≥ 2 - 5

x ≥ - 3

or

x + 5 ≤ -2

x ≤ - 2 - 5

x ≤ - 7

<---- -7]------[-3---->

Correct?
 
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  • #2
Both are correct.
 
  • #3
It surely feels good to be right.
 

1. What is an interval on a number line?

An interval on a number line is a set of numbers represented by a line segment on a number line. It includes all the numbers between two given points, including the endpoints.

2. How are intervals written on a number line?

Intervals on a number line are typically written in the form of [a, b], where a and b represent the endpoints of the interval. The square brackets indicate that the endpoints are included in the interval.

3. What is the difference between an open and a closed interval on a number line?

An open interval does not include its endpoints, indicated by parentheses in its notation, (a, b). A closed interval, on the other hand, includes its endpoints, as represented by square brackets in its notation, [a, b].

4. Can intervals on a number line be infinite?

Yes, intervals on a number line can be infinite. An infinite interval is represented by using the infinity symbol (∞) in its notation. For example, an interval from 3 to infinity would be written as [3, ∞).

5. How are intervals used in mathematics?

Intervals on a number line are commonly used in mathematics to represent ranges of numbers, such as in inequalities and graphs. They are also used in calculus to represent the domain and range of functions and to determine limits and continuity.

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