Just want to double check that I am doing these right. Not looking for an answer.

5p^4q - 20q^3 should = 5pq(p^3-4q^2) right?

72x^2 - 2y^2 should = (2y-3x) (2y-36x) right?

Thanks so much!

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- Dec 12th 2008, 12:37 PMtpomajust checking that I got these right
Just want to double check that I am doing these right. Not looking for an answer.

5p^4q - 20q^3 should = 5pq(p^3-4q^2) right?

72x^2 - 2y^2 should = (2y-3x) (2y-36x) right?

Thanks so much! - Dec 12th 2008, 12:41 PMchella182
Well the first one is wrong because if you multiply out your answer you get , which isn't what you have on the left-hand side. In other words, you can't take a outside the bracket.

I don't think the second one is right either because multiplying that out you'd get or which again isn't what you have on the left-hand side. - Dec 12th 2008, 12:48 PMtpoma
ok re-do

5p^4q - 20q^3 should have been 5q(p^4-4q^2)

Will have to work on the second one..... - Dec 12th 2008, 12:52 PMmasters
Find your greatest common factor over your two terms

The common factor is 5q. Factor that out and you have:

Find your GCF again. That would be 2. Factor that out.

Inspecting the binomial, you should notice that it is the difference of two squares and factors in this manner:

So, finally we have:

- Dec 12th 2008, 12:56 PMtpoma
- Dec 12th 2008, 01:08 PMmasters

The Brain -- is wider than the Sky --

For -- put them side by side --

The one the other will contain

With ease -- and You -- beside --

The Brain is deeper than the sea --

For -- hold them -- Blue to Blue --

The one the other will absorb --

As Sponges -- Buckets -- do --

The Brain is just the weight of God --

For -- Heft them -- Pound for Pound --

And they will differ -- if they do --

As Syllable from Sound --

*Emily Dickenson (w.1955)* - Dec 12th 2008, 01:38 PMtpoma
Ok got one more for you, and hopefully the last one....lol

c^2 - 3cd - 18d^2

is this correct?

3(cd + 6d^2 - c^2) = 3c(d+2d^2 - c) gee I hope so!! - Dec 12th 2008, 01:48 PMchella182
You can't take a three out because there isn't a 3 in every term (the term). You can't take a out either because there's no in the term.

- Dec 12th 2008, 01:57 PMtpoma

Ok so.....once again I am not able to do anything with this problem because it is not factorable....there is not a c, d, or a number in each term, so again my answer would be__not able to factor__. Why would my professor put these on here to be factored completely if you can not factor at all? (Headbang) - Dec 12th 2008, 02:04 PMmasters
I hate to burst your bubble, but is a common factor of your trinomial expression.

You must factor this as a trinomial. There are different techniques people use to do this, but here I might suggest the "guess and check" method.

If factorable, a trinomial will be the product of two binomials. So, let's start there.

Now, factoring the first term is easy:

Now, look at the last term coefficient . We need to find two factors that multiply together to make and add together to make your middle term coefficient . This is the guess and check part.

Try various factors of

This pair is no good because they don't add to

This pair works because they add to

So, let us finish filling in the two binomial factors. By the way, don't forget that there's a attached to that we just factored.

There you have it. - Dec 12th 2008, 02:05 PMchella182
Actually...

is the answer. If you multiply out those brackets you should get what you started with.

Darn, got beaten to it (Giggle) I am so slow at factorising stuff like that. - Dec 12th 2008, 02:18 PMtpoma
OH brother! You make that look so easy! (Giggle) Thanks!

- Dec 12th 2008, 02:34 PMtpomaLast one I PROMISE!
Last one I PROMISE!

is this correct.....just a plain yes or no answer.

49x^2 + 140x + 100

answer should be......(7x + 10) (7x + 10) right???? Please say yes..lol(Lipssealed) - Dec 12th 2008, 07:38 PMmasters
- Dec 13th 2008, 09:35 PMgreat_math