Absolute Value

πŸ†Practice absolute value

Absolute Value

Absolute value is denoted by || and represents the distance from zero.
The absolute value of a positive number - will always be the number itself.
For example: β”‚2β”‚=2β”‚2β”‚= 2
The absolute value of a negative number - will always be the same number but positive.
For example: β”‚βˆ’3β”‚=3β”‚-3β”‚=3
Note that the absolute value of a number will always be positive since distance is always positive.

Absolute Value in an Equation with a Variable

If we have an unknown or an expression with an unknown inside absolute value, we ask ourselves which expression will give us the desired equation value, split into cases and find the unknown.
For example in the equation: β”‚x+7β”‚=12β”‚x+7β”‚=12
We ask ourselves, which expression in absolute value will equal 12.
The answer will be 12 or -12. (both 12 in absolute value equals 12 and -12 in absolute value equals 12).
Therefore, we'll take the entire expression and split it into two cases:
First case:
x+7=12x+7=12
Let's solve:
x=5x=5

Second case:
X+7=βˆ’12X+7=-12
Let's solve:
x=βˆ’19x=-19

Therefore, the solution to the exercise is: x=5,βˆ’19x=5,-19

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Test yourself on absolute value!

Determine the absolute value of the following number:

\( \left|18\right|= \)

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Solving Absolute Value Inequalities and Their Interpretation

Understanding absolute value is crucial when solving inequalities involving absolute values. An absolute value inequality expresses the range of values that a variable can take, based on its distance from zero on the number line. For example, consider the inequality ∣x∣<5∣x∣<5. This inequality states that the absolute value of xx is less than 5, meaning xx is within 5 units of zero. Therefore, xx can be any value between -5 and 5, not including -5 and 5 themselves. In interval notation, this is written as βˆ’5<x<5-5 < x < 5. To solve absolute value inequalities, we often split them into two separate inequalities: one representing the positive scenario and the other the negative. This method allows us to find all possible values of the variable that satisfy the original inequality. Mastering this technique is essential for accurately solving and graphing solutions to absolute value inequalities.

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Examples with solutions for Absolute value

Exercise #1

βˆ£βˆ’712∣= \left|-7\frac{1}{2}\right|=

Step-by-Step Solution

The absolute value of a number is always its positive value. It represents the distance of the number from zero on the number line, regardless of direction. The absolute value of any negative number is its opposite positive number.

Step 1: Identify the number to find the absolute value of: βˆ’712 -7\frac{1}{2}

Step 2: Change the negative sign to positive: 712 7\frac{1}{2}

Hence, the absolute value of βˆ’712 -7\frac{1}{2} is 712 7\frac{1}{2} .

Answer

712 7\frac{1}{2}

Exercise #2

∣0.8∣= \left|0.8\right|=

Video Solution

Step-by-Step Solution

To find the absolute value of 0.80.8, we will use the definition of absolute value, which states:

  • If a number xx is positive or zero, then its absolute value is the same number: ∣x∣=x|x| = x.
  • If a number xx is negative, then its absolute value is the positive version of that number: ∣x∣=βˆ’x|x| = -x.

Let's apply this to our problem:

Since 0.80.8 is a positive number, its absolute value is simply itself:

∣0.8∣=0.8|0.8| = 0.8

Therefore, the absolute value of 0.80.8 is 0.80.8.

Looking at the given answer choices:

  • Choice 1: "There is no absolute value" is incorrect, as every real number has an absolute value.
  • Choice 2: βˆ’0.8-0.8 is incorrect, because absolute values are never negative.
  • Choice 3: 00 is incorrect, as the number is not zero.
  • Choice 4: 0.80.8 is correct, as it matches the calculated absolute value.

Thus, the correct choice is 0.80.8.

Therefore, the solution to the problem is 0.80.8.

Answer

0.8 0.8

Exercise #3

βˆ£βˆ’434∣= \left|-4\frac{3}{4}\right|=

Step-by-Step Solution

The absolute value of a number is the positive form of that number, representing its distance from zero on the number line.

Step 1: Identify the number whose absolute value is needed: βˆ’434 -4\frac{3}{4}

Step 2: Remove the negative sign from the number: 434 4\frac{3}{4}

Thus, the absolute value of βˆ’434 -4\frac{3}{4} is 434 4\frac{3}{4} .

Answer

434 4\frac{3}{4}

Exercise #4

Determine the absolute value of the following number:

βˆ£βˆ’25∣= \left|-25\right|=

Step-by-Step Solution

The absolute value of a number is the distance of the number from zero on a number line, without considering its direction. For the number βˆ’25 -25 , the absolute value is 25 25 because it is 25 units away from zero without considering the negative sign.

Answer

25 25

Exercise #5

βˆ£βˆ’1914∣= \left|-19\frac{1}{4}\right|=

Video Solution

Step-by-Step Solution

These signs in the exercises refer to the concept of "absolute value",

In absolute value we don't have "negative" or "positive", instead we measure the distance from point 0,

In other words, we always "cancel out" the negative signs.

In this exercise, we'll change the minus to a plus sign, and simply remain with 19 and a quarter.

And that's the solution!

Answer

1914 19\frac{1}{4}

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