Good morning Sonia! This is an extension of what you have learnt in quadratic inequalities two years ago.

In fact, this approach I have done now can be used for quadratic inequalities as well! Except that you learnt to draw a quadratic curve for the quadratic inequality when you learnt them two years ago.

Here, we must be careful with the inequality as the presence of the square root means that x cannot be negative as well.

Sonia, let me know if you need more explanation.