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Absolute value shows how far a number is from zero on a number line. Since distance is always positive, absolute value is always a positive number. For example:
|3| = 3, because 3 is 3 units from zero.
|-3| = 3, because -3 is also 3 units from zero.
When you see an equation like |x| = 3, it means two things:
x = 3 (because 3 is 3 units from zero)
x = 3 (because -3 is also 3 units from zero)
If you see something like |x| = -3, there’s no solution. Why? Because absolute value can’t be negative!
Consider |x + 2| = 5
Solve |x + 2| = 5 for the + side of the number line:
|x + 2| = 5
x + 2 = 5
-2 -2
x = 3
Solve |x + 2| = 5 for the NEGATIVE side of the number line:
|x + 2| = 5
Set 5 to negative.
x + 2 = -5
-2 -2
x = -7
Substitute each answer back into the original equation to make sure both solutions work.
|x + 2| = 5
|3 + 2| = 5
|5| = 5
5 = 5 ✔
Substitute each answer back into the original equation to make sure both solutions work.
|x + 2| = 5
|-7 + 2| = 5
|-5| = 5
5 = 5 ✔
Consider 5 + |x + 6| = 7
Solve 5 + |x + 6| = 7 for the + side of the number line:
5 + |x + 6| = 7
Subtract the 5:
5 + |x + 6| = 7
-5 -5
|x + 6| = 2
Remove the brackets and subtract the 6:
x + 6 = 2
-6 -6
x = -4
Solve 5 + |x + 6| = 7 for the NEGATIVE side of the number line:
Start with this:
|x + 6| = 2
Set the 2 to Negative:
|x + 6| = -2
Remove the brackets and subtract the 6:
x + 6 = -2
-6 -6
x = -8