Algebra help please!!

[cphillips]

I'm wanting to achive my highschool graduation through at home correspondence, I'm a mother of 3 young children so doing my schooling at home is the best way for me to complete it and be there for my children. Right now I'm working on a practise exercise worksheet to see what I know and what I need to refresh my memory on and also for what course they should put me in.


Sorry I didn't respond earlier, been watching LOTS of videos but the answer I came up with for factoring: a^3-4a = a(a-2)(a+2)

[Denis]

Sorry I didn't respond earlier, been watching LOTS of videos but the answer I came up with for factoring: a^3-4a = a(a-2)(a+2)

Good one, Mom...there's still hope for you

[cphillips]

HEHE thanks, its starting to come back to me and so is the headache

[Denis]

Mom, these "factor" things kinda go this way:

some teacher wrote down something like (2x + 3)(x - 5)

then multiplied it out: 2x^2 + 3x - 10x - 15 ; 2x^2 - 7x - 15

then told YOU: factor this : 2x^2 - 7x - 15

and YOU have to come up with what he multiplied out....

[cphillips]

Ok, so I'm starting to get used to factoring like terms with the same variable again but this next one I'm realy stumped on, has no GCF and the variables are different, been looking at so many vid's and other algebra help sites trying to find an equation similar and so far haven't, please help!!

Need to factor each completey:

1) 6x^2 +13x -5= (3x -1)(2x+5) I think i got this 1 ??
x=1/3 x=-5/2

2) 9x^2 - 16y^2= This one the only thing in common is the ^2 but trying to work it out this doesn't work, (x-y)(9x - 16y), and I have no clue what else to do for this


3) 16x^2 - 24xy + 9y^ This one I had no clue where to even begin

[Denis]

1) 6x^2 +13x -5= (3x -1)(2x+5) I think i got this 1 ??
x=1/3 x=-5/2

Correct. You can make sure you're correct by multiplying out your 2 factors:
3x - 1
2x + 5
======
-5 + 15x (multiply top by 5)
-2x + 6x^2 (multiply top by 2x)
Add 'em up: -5 + 15x - 2x + 6x^2 = 6x^2 + 13x - 5 : voila!

2) 9x^2 - 16y^2= This one the only thing in common is the ^2 but trying to work it out this doesn't work,
(x-y)(9x - 16y), and I have no clue what else to do for this.

Real easy: go here:
http://www.google.ca/search?hl=en&sourc ... ference+of
Are you ok now?

3) 16x^2 - 24xy + 9y^2 This one I had no clue where to even begin

Try 16x^2 - 24x + 9 ; get my drift?

[stapel]

3) 16x^2 - 24xy + 9y^2 This one I had no clue where to even begin

You would factor this in exactly the same way that you would factor 16x[sup:ablvqhu9]2[/sup:ablvqhu9] - 24x + 9, except that your factors will have a "y" at the ends, instead of only an "x" at their beginnings.

Hint: Perfect square trinomial....

[cphillips]

Is this right or can i factor this even more to be completely factored.

9x^2 -16y^2= ( 3x -4y)(3x +4y)

16x^2 -24xy +9y^2= (3y -4x)(3y-4x)

[stapel]

Once you get down to linear expressions (such as 3x + 4), and as long as nothing factors out (as would happen with 2x + 4), you're done!

[cphillips]

Great, thx so much everyone mabe I won't be quite so lost once I actually start a course where algebra is concerned now on to remembering geometry and trig