Before we get into solving absolute value equations, let's first quickly review what the term "absolute value" means.
Did you notice how in the above examples, the answers of 10 and 55 were the same for two different expressions?
By this I mean that: |-10| = 10 and |10| = 10.
Two different expressions have an
answer of 10 because the absolute value of a number is always positive.
This concept will play an important role as we solve absolute value equations. Pay careful attention because many of your equations will have two answers.
You must remember that when you are solving an absolute value equation, you will want to write two separate equations to solve. This is because the value inside of the absolute value bars can be positive or negative to result in the same answer.
Let's take a look at another similar example just to clarify any problems or questions.
I hope that you are feeling more comfortable with absolute value equations. There is a time when you may not have a solution. Yes, there always has to be tricks, just to keep you on your toes.
When working with absolute value, think about what might not be possible...
What would you substitute for x in the following equations to make the equation true?
|x| = -3
Can you think of an answer for x? Probably not, because there is no answer. There is no way that you can take the absolute value of a number and have a negative answer.
Therefore, if you come across an equation, such as the following:
|x - 5| = -4
You can stop right there and write the empty set as your answer.
You do not have to write two equations and solve, because there are no real answers to this equation.
Do not write 0 as your answer. The answer is the empty set and is written as follows: