View Full Version : Math help... I feel so stupid.

August 21st, 2007, 12:02 AM
Hey, I figure theres a lot of you guys out there who kick *** at the mathematics, and if you could help me out with this I'd be super happy.

Anyway, I'm going into AP calc this year (senior of highschool), and our teacher handed out a packet of stuff to do over summer just so we don't get rusty. I've gone through the entire thing without a hitch (they're supposed to be god-awful easy), but there's one I can't get for the life of me.

The problem is:

2x^3 - 11x^2 +12x +9

Nothing I've used before to solve problems like this is working! The only progress I've made (with the help of good ol' graphing calculator) is that the value of the function is 0 when x is .5 or 3.

Any help would be greatly appreciated, fellow ubuntians.

August 21st, 2007, 12:04 AM
I used my TI-89 and got (x-3)^2(2x+1)

August 21st, 2007, 12:12 AM
sweeeet. I'm stuck with the 83, but its usually enough for my needs.

August 21st, 2007, 12:19 AM
The Ti-89 saved my life many times through Uni (or College if you will).

Though of course... I cheated with the inbuilt text editor during a few exams. I can say that now since those days are long gone. :)

Which could be considered bad advice, umm...


August 21st, 2007, 12:46 AM
Yeah now they freak out if you have a calculator on your desk during non-math sections of the SAT. That even counts as cause to confiscate it :S.

August 21st, 2007, 01:05 AM
Thought I had it, but it's not the same answer as posted above.

August 21st, 2007, 01:30 AM
what format do you want it in? i worked it out and i think these are the x intercepts at least:

x = 1
x = 3
x = 3/2

im really rustt on this stuff... so i COULD be wrong (summer vacation anyone?) and i had to dig out my old algebra notebooks to figure it out, if you want my work i could scan it ;)

August 21st, 2007, 03:27 AM
I'd be willing to guess your teacher wants you to be comfortable with the rational zeros theorem. (http://www.sparknotes.com/math/algebra2/polynomials/section4.rhtml)

I too have a TI-89. I bought it when I learned I could use it on my math certification exam. I remember rubbing my eyes and looking at the list of allowed calculators and saying, "Really? They'd let me use a TI-89?! I'll buy one just for that damned test!". :)