Question 969032
WHEN y=ax^2+bx+c>0, can u tell me why the graph must be above the x-axis?
<pre>
Look at this set of axes:

{{{graph(400,400,-10,10,-10,10,15)}}}

All the numbers marked on the y-axis above the x-axis are all positive.
All the numbers marked on the y-axis below the x-axis are all negative.

The positive numbers are the numbers greater than 0.
The negative numbers are the numbers less than 0.

Your inequality states:

y = ax^2+bx+c > 0

The important thing is that it says that y > 0,
or y is greater than 0, which means that y is positive.

So that can only be where the y-axis has positive numbers 
marked on it, which is above the x-axis.

Edwin</pre>