Ask your own question, for FREE!
Mathematics 18 Online
lock:

how to divide these help

lock:

http://prntscr.com/ls85dn

Hero:

You should factor them first

lock:

individually?

Hero:

There are two expressions. Factor both completely first.

lock:

1,-1

Hero:

?

lock:

my bad (x-1)(x-1)

Hero:

Can you post the steps to how you got that?

lock:

sorry i used a calc

lock:

i will look up an example and try to solve it give me a sec

lock:

for the second one is it (x-1)^2

Hero:

correct

lock:

and the first one is the same but with a ^3?

lock:

(x-1)^3

Hero:

What do you mean? Show all your steps

Hero:

no thatsnot right

lock:

oh

lock:

hm

Hero:

What does \(x^3 - 3x^2\) factor to?

lock:

x^2(x-3)

lock:

nvm

Hero:

Hang on a minute let me post these there.

Hero:

1544240380-5c0b36fb74d975b63317f400-PolyDivide.png

lock:

much better

Hero:

Okay now we will deal with this right. \(x^3 - 3x^2 + 3x -1\)

lock:

correct

Hero:

Give me a minute...

lock:

take your time

Hero:

Let's see what happens if we do it this way: \(x^3 - 1 - 3x^2 + 3x\)

Hero:

If we re-write it this way then the first two terms is a difference of cubes since \(1^3 = 1\) so: \(x^3 - 1^3 - 3x^2 + 3x\)

Hero:

Remember that formula for difference of cubes is \(a^3 - b^3 = (a - b)(a^2 + ab + b^2)\)

lock:

can we rewrite it this way for every factoring question ?

Hero:

In other words, we can re-write the expression as: \((x - 3)(x^2 - x + 1) - 3x^2 + 3x\)

Hero:

No, there's different polynomials that require different approaches.

lock:

oh ok

Hero:

Anyway, the next step is to factor the last two terms. Wanna give it a try? Don't use a calc though

Hero:

Oh I made a mistake

Hero:

The difference of cubes for the first two terms factor to: \((x - 1)(x^2 - x + 1) - 3x^2 + 3x\)

Hero:

There we go, now we can factor the last two terms.

lock:

how do i factor this (x−1)(x2−x+1)−3x2+3x? like how would i divide it?

Hero:

Don't worry about dividing right now. We're factoring. I asked you to factor the last two terms of that expression. And please use \(\LaTeX\) to write. It's bad style to write the expressions the way you do without using caret symbols for the exponent.

lock:

ok

lock:

3x(x+1)

Hero:

I can't even be mad with you because I made another mistake with my factorization, but with yours, you factored out $3x$ instead of $-3x$

lock:

lol

lock:

oh so 3x(-x+1)

Hero:

Here's the correct factorization: \(\begin{align*} x^3 - 3x^3 + 3x - 1&=x^3 - 1^3 - 3x^3 + 3x \\ &=(x - 1)(x^2 + x + 1) - 3x(x - 1)\\ &=(x - 1)(x^2 + x + 1) \end{align*}\)

Hero:

You factor out \(-3x\) because its common to both terms

Hero:

Now that we have the correct factors, NOW we can divide: \( \begin{align*} \dfrac{x^3 - 3x^2 + 3x - 1}{x^2 - 2x + 1}&=\dfrac{(x - 1)(x^2 + x + 1)}{(x - 1)^2} \end{align*} \)

lock:

my eyes

Hero:

And when you divide, you're mostly cancelling factors of one. Notice we can re-write what we factored as a product of one and the remaining factors \( \begin{align*} \dfrac{(x-1)(x^2 + x + 1)}{(x - 1)^2} = \dfrac{x - 1}{x - 1} \cdot \dfrac{(x^2 + x + 1)}{x - 1} \end{align*} \)

Hero:

And of course the factors of one cancel to get just: \(\dfrac{x^2 + x + 1}{x - 1}\)

Hero:

Which cannot be factored any further.

lock:

i cant cancel out variables?

Hero:

You can only cancel out matching factors in the numerator and denominator but we canceled those already.

lock:

what about the two x's?

lock:

there is a positive one on the num and denom

Hero:

you should really review your factoring. You should not be attempting to divide polynomials without mastering how to factor them.

lock:

yes will do thank you verry much !

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!