The two dashes around x-3 represent a modulus. What a modulus does is that it converts whatever is inside it to a positive. So that would mean there are two possible values that would give us 0 a positive x-3 and a negative x-3 meaning -x+3. That would mean x becomes 3 in both the situations.
- x-3=0 and -x+3=0
The Modulus Function, |x| : ExamSolutions
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