(x+3)(x-5)(x-2)?

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lymepink

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The question says write a polynomial in standard form using the following zeros: -3,5,2.
I got it down to the step of (x+3)(x-5)(x-2) but i dont know how to multiply those together.. fast help would be wonderful. Darn final tomorrow.
 
It is just multiplication. Why are you struggling with this? Surely you have multiplied binomials before. No?
 
lymepink said:
If I knew how to do it, I wouldn't have posted it.
Click to expand...

You have this quite backwards. It's the stuff you cannot post that is what you don't know.

So, you're actually saying you cannot expand this multiplication of binomials (x + 1) * (x + 2) into its equivalent trinomial?

Please try. Really, it's just multiplication - just like 23 * 47.
 


Please go to purplemath.com (or google.com) and search using keyword FOIL.

FOIL is an acronym for "First-Outside-Inside-Last". These are four steps that comprise an algorithm for multiplying two binomials.

There are lots of examples and lessons. Come back here and post any specific questions that arise.

Here is FOIL symbolically:

(a + b)*(c + d) = a*c + a*d + b*c + b*d

 
I know how to foil a set, it just slipped my mind how to multiply these three together. So far no one has even posted the answer...
but it's fine now because I figured it out this morning, I was just hoping someone would post a fast answer last night while I was doing my review sheet. I don't know how this site works exactly. Thanks for the suggestions.

And tkhunny or whatever your name is, your last comment didn't even make sense. Stop trying to get smart on a math website people use for help. I obviously forgot how to do the problem, I don't need someone telling me how I dont know how to do a problem. It would have been much appreciated for help, not for your irrelevant comments.
 
What did you do to solve it? Was it something other than multiplication?
 
The question says write a polynomial in standard form using the following zeros: -3,5,2.
I got it down to the step of (x+3)(x-5)(x-2)
Click to expand...

The multiplication is simple. Start by multiplying any two of the factors -- for example, the first two: x^2 - 2x - 15. Now just multiply each of these three terms by the remaining two terms.
 
lymepink said:
I know how to foil a set, it just slipped my mind how to multiply these three together.
Click to expand...

lymepink,

also the multiplication can be done in a vertical style:


\(\displaystyle - \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \longrightspace \ \ \ \ \ \ \ x^2 \ \ - \ 2x \ \ - \ 15\)
\(\displaystyle - \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \longrightspace \longrightspace \longrightspace \ \ \ \ \ x \ \ - \ \ \ 2\)
\(\displaystyle .- \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ ---------\)
\(\displaystyle - \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ -2x^2 \ \ + \ \ \ 4x \ + \ 30\)
\(\displaystyle - \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x^3 \ \ - \ 2x^2 \ \ - \ 15x\)
\(\displaystyle .- \ \ \ \ \ \ \ \ \ \ \ \ \ -- - - - - - - - - - - -\)
\(\displaystyle - \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x^3 \ \ \ - \ 4x^2 \ - \ \ 11x \ + \ 30\)


Also, see this for vertical style examples:

http://www.purplemath.com/modules/polymult.htm
 
LymePink, I'm kind of a positional freak (like, I throw with my left hand, do everything else with my right hand!);
with these, I'm only comfortable if I go left to right this way:
Code: 
x^2 - 2x - 15
x - 2
================
x^3 - 2x^2 - 15x
    - 2x^2 +  4x + 30
=====================
x^3 - 4x^2 - 11x + 30
Try it, perhaps you'll like it :idea:
 
lymepink said:
So far no one has even posted the answer ...

I was just hoping someone would post a fast answer last night

That's not how it works, at this site.


I don't know how this site works exactly.

Please review the post titled, "Read Before Posting". 8-)

Click to expand...
 
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