In practice, I would write the three cases separately and clearly note the side condition (x = 0, x > 0, x < 0) for each case. After solving each case, it is important not to forget and combine the solution with the side conditions using "and," and then combine the solutions for different cases using "or."
is equivalent to
In this case, it can be verified in two ways. First,
Alternatively, you can move a point along the x-axis from 0 to the right or to the left and see where the inequality becomes true.
Remember that you need to take only the positive solutions from the second case.