# Math Help - Quadratics Review

If anyone wouldnt mind, I would really appreciate it if someone would take a look at my work....I had to do this review, but I am not totally sure if I am doing these problems correctly..There are about 5 problems...you dont have to check them all, but I would really like to make sure that I am on the right track...thanks

2. Originally Posted by aikenfan
If anyone wouldnt mind, I would really appreciate it if someone would take a look at my work....I had to do this review, but I am not totally sure if I am doing these problems correctly..There are about 5 problems...you dont have to check them all, but I would really like to make sure that I am on the right track...thanks

I don't have time to look at much, but for 1b) note that when you take the square root the LHS gets a $\pm$ on it, so there are two solutions, not one. The rest of problem 1 is correct.

-Dan

3. Thank you for all of your help!

4. Originally Posted by aikenfan
If anyone wouldnt mind, I would really appreciate it if someone would take a look at my work....I had to do this review, but I am not totally sure if I am doing these problems correctly..There are about 5 problems...you dont have to check them all, but I would really like to make sure that I am on the right track...thanks

I get 3 zeros for 3a) and for 3b) I get x = 3 is exact.

For 10 you can do this in a much simpler way, assuming you don't have to put the parabola in "standard form."

A general form for a parabola is
$y = a(x - r_1)(x - r_2)$
where $r_1 \text{ and }r_2$ are the zeros of the parabola.

So two possible answers would be:
$y = (x - 3)(x + 5) = x^2 + 2x - 15$<-- Opens upward
and
$y = -(x - 3)(x + 5) = -x^2 - 2x + 15$<-- Opens downward

-Dan

5. Thank you! Would 10 be correct the way it is, though? That is the way that we were taught to do them.

6. For the third zero on 3a) I get 2.115

7. Originally Posted by aikenfan
Thank you! Would 10 be correct the way it is, though? That is the way that we were taught to do them.
You lost a negative sign on the downward opening parabola. Otherwise, yes.

-Dan

8. Originally Posted by aikenfan
For the third zero on 3a) I get 2.115
Looks good to me.

This is not the first time you have missed a zero on one of these. Make sure you are looking at enough of the x-axis that you are absolutely certain you have all of them.

-Dan

9. Thank you very much for all of the help!