9709 Pure 1 · 1.1 Quadratics · Session 2
Two things live here. Practice gives you a question and you tap the answer straight onto the number line, then it shows you why. Explore is the full instrument: set both critical values, flip the curve, pick any of the four inequalities, and watch the sketch and the sign table agree.
Solve this
Set the two critical values, pick which way the parabola opens, pick an inequality. The solution set reads straight off the sketch, and the sign table underneath gets there the other way. Open circles mean the endpoint is left out. Filled circles mean it is included.