# Quadratics: need help checking work

• September 24th 2007, 02:38 PM
aikenfan
I did all of these questions, but i want to be sure that i did not make any mistakes...im not sure if I am doing these right...you dont have to check them all, but i would really appreciate it if someone would take a look at a few of them....thank you very much

http://i103.photobucket.com/albums/m...9/111001-1.jpg

http://i103.photobucket.com/albums/m...9/111002-1.jpg
• September 25th 2007, 05:58 AM
topsquark
Quote:

Originally Posted by aikenfan
I did all of these questions, but i want to be sure that i did not make any mistakes...im not sure if I am doing these right...you dont have to check them all, but i would really appreciate it if someone would take a look at a few of them....thank you very much

http://i103.photobucket.com/albums/m...9/111001-1.jpg

http://i103.photobucket.com/albums/m...9/111002-1.jpg

It all looks good except for 7. (Which, by the way, you could have checked on your own by simply multiplying it back out.)

Look at the sign on the -2x. It should be positive since you are subtracting $x^4 - 2x^3$ on the second line.

-Dan
• September 25th 2007, 06:57 AM
DivideBy0
I don't like the question wording... I'd be more comfortable with

4. Find the local extrema

5. Find the zeros. Of course, there are infinite solutions to $y=3x^2-11x-20$.