# Math Help - Factoring a quadratic equation

1. ## Re: Factoring a quadratic equation

Originally Posted by Siron
Ok, then what you wright is good enough.
Thanks Siron, much appreciated, everything I am doing is a new learning curve for me.

I have a new question.

A parabola is U shaped. My understanding is that this U shape is +
The parabola has axis of symmetry x = 0
The parabola has y intercept (0, - 2)
The points (2, 0) lies on the parabola

I am asked to find the equation, which I think I got it right here;

y = 1/2 x^2 - 2
y = 1/2 x 4 - 2
y = 0

How am I doing?

2. ## Re: Factoring a quadratic equation

$y=\frac{1}{2}x^2-2$ looks good.
Check:
Does the parabola goes through the points $(0,-2)$ and $(2,0)$: yes!

3. ## Re: Factoring a quadratic equation

Originally Posted by Siron
$y=\frac{1}{2}x^2-2$ looks good.
Check:
Does the parabola goes through the points $(0,-2)$ and $(2,0)$: yes!
I have only scetched it by hand, the parabola goes through 2 and - 2, but I am not understanding y = 0 at the moment, x = 0 and y = 0 not fully understood at the moment?

please explain it if you can?

4. ## Re: Factoring a quadratic equation

Okay, for example. Can you determine where the point $(0,2)$ lies ...? On the x-axis? On the y-axis? Why? ...

5. ## Re: Factoring a quadratic equation

Originally Posted by Siron
Okay, for example. Can you determine where the point $(0,2)$ lies ...? On the x-axis? On the y-axis? Why? ...
Not to sure what you mean?

(0, 2) means 0 = x axis and 2 = y axis, I don't understand anymore at the moment?

6. ## Re: Factoring a quadratic equation

Okay, 0 we call the x-coordinate and 2 we call the y-coordinate. Can you be more clear about what you don't understand about $x=0$, $y=0$, ...
The (straight) lines:
$x=0$: y-axis
$y=0$: x-axis

7. ## Re: Factoring a quadratic equation

@David:

Do you understand it now? Or? ...

8. ## Re: Factoring a quadratic equation

we did not talk about it. because its very long question. sorry.

9. ## Re: Factoring a quadratic equation

Originally Posted by grouponclonescript
we did not talk about it. because its very long question. sorry.
What do you mean? ...

10. ## Re: Factoring a quadratic equation

Originally Posted by Siron
@David:

Do you understand it now? Or? ...
Siron, I will need to read up and ask questions I think?

I am not sure how to interpret what is being said, suppose I had a graph y = x^2 - 3x - 10, then suppose that the graph is a + parabola, y is the intercept where it crosses or touches the y axis, but that is it is a value of y when x = 0, but then the x intercepts are - 2, 5, y intercept is - 10.

So the graph is such that the parabola is drawn from the second quadrant down crosses the x axis at -2 then passes through the third quadrant then crosses the y axis at - 10, then turns and goes up through the fourth quadrant cutting the x axis at 5, then entering the first quadrant to finish.

Thats a lot of information to try and understand how x = 0 and y = 0, I don't understand how they relate together?

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