Sir how do you tell I the x is inside or outside the line, is that something to do with the zero test ?
Yes that is what the zero test is for.
To think of it another way. After solving the related quadratic equation you have to ask do values of x between the solutions agree with the inequality or is it values outside? You can sub in any x value to check. Zero is just an easy one to use.
The shape of the graph can be used instead of the zero test.
Have a look at the video examples again.
Okie dokie thanks sir