1. ## Quadratic Inequalities.

I do NOT understand how to do this. Can someone explain in full detail/step by step how to do it? Which points in the end would I graph? (for each problem)

1) y > -x^2 -10x

2) y< 4x^2+8x+4

3) y>x^2-3x-18

2. Originally Posted by SpaceGhost

1) y > -x^2 -10x
$y > -x^2 -10x \implies y> -x(x+10)$

Solving gives us $x = 0,-10$ which serve as the x-axis intercepts for the inverted parabola. Graph the parabola and you have two reigions on your plane, we now have to decide which region is required.

So choose a point anywhere i.e. $(-5,0)$ and substitute into the equation.

If this statement is correct then this point falls in the required region, otherwise if false, reject this region and choose the other.

$0 > -(-5)^2 -10(-5) \implies 0 > -25+50$ which is false so reject this region.

3. Sorry I'm still a little confused. Which is the vertex? And do I graph: (10,0 and -10,-0) or (0,0 and -10, 0)

4. Grpah these two points and the parabola that passes through it.

Originally Posted by SpaceGhost
(0,0 and -10, 0)
The vertex is not required.

5. I need more help with these. :S I need to have 5 ordered pairs for each.

I need to find the vertex, all x-intercepts, y-intercepts, and 2 "partnered pairs"