# Polynomials: K(cubed) - 30K- 18 - 4K(squared) by 3+K

#### BabyBlue

##### New member
I need help with another one: K (cubed)- 0K (squared)- 30K- 18-4K(squared)- 0K by 3+K

I hope I added in the zeros correctly
It was originally: K cubed- 30K-18-4K squared by 3+K
Hope I am not being a bug,
Amy
:?:

#### Mrspi

##### Senior Member
Re: Polynomials again

BabyBlue said:
I need help with another one: K (cubed)- 0K (squared)- 30K- 18-4K(squared)- 0K by 3+K

I hope I added in the zeros correctly
It was originally: K cubed- 30K-18-4K squared by 3+K
Hope I am not being a bug,
Amy
:?:
First step is to write the dividend (the expression you're dividing INTO) and the divisor (the expression you're dividing BY) in the same order.

Usually, it is best to write dividend and divisor in "descending order," highest power of the variable to lowest power of the variable.

If we do this, we have

(k<SUP>3</SUP> - 4k<SUP>2</SUP> - 30k - 18) divided by (k + 3)

Ok...now, the long division process is similar to what you learned in grade school. Here's a website which "walks you through" the process. http://www.purplemath.com/modules/polydiv2.htm

Study the website, and see what you can do with your problem. If you still have trouble, please repost showing all of the work you have done.

#### BabyBlue

##### New member
Thanks for replying so fast, I guess I forgot to read the thing about letting the people see your work, so they won't think your just trying to get them to solve the problem for them. Believe me, I have been reading up on this, I read all the things on Purple math, and finally (the most helpful for me) I read the intermediate algebra website.

Now, about the problem I am having. You said you should arrange it in the order of the divisor. So, the long division problem: (Kcubed-30K-18-4Ksquared) divided by (3+K)

So I would need to do this:
(0K-Ok sqaured- K cubed- 30K- 18- 4K squared)?

I just need a little help on the set up.

Thanks,
Amy

#### galactus

##### Super Moderator
Staff member
Set it up like so:

Here's a start:

Code:
    k^2
------------------------------
k+3|k^3 - 4k^2 - 30k - 18
k^3 + 3k^2
----------------------------
7k^2  -30k   -18

Now, finish up?.

#### skeeter

##### Senior Member
correct the typo (should be negative 7k^2) in the last line ...

Code:
    k^2
------------------------------
k+3|k^3 - 4k^2 - 30k - 18
k^3 + 3k^2
----------------------------
-7k^2  -30k   -18

#### BabyBlue

##### New member
Thanks, I got the right answer I think
It is: K squared-7K-9
fraction positive 9 over 3+K
I guess I was just confused.

From now on I know adding zeros is not always the answer.

If someone else ever needs help with dividing polynomials they should go to:
Thanks,
Amy

#### Denis

##### Senior Member
Amy, start posting k squared this way: k^2
or k cubed: k^3 ...and so on

And square root of k: sqrt(k)

Ok. Sorry :wink: