I have 5 questions that involve factoring the difference and sum of cubes. Can anyone please help me out with them? This is the first one: Choose one of the factors of 24x^6 – 1029y^3 3 2x^2 – 7y 4x^4 + 14x^2y + 49y^2 All of the above
Alright, so you just find CGF, and ... I don't quite understand the setting the numbers up as cubes.
Where do you get the 4x^4 from? ... and all the other numbers in that factor from?
@etenraku1
one second.
Alright.
Choose one of the factors of 5x^3 – 135 5 x – 3 x^2 + 3x + 9 All of the above This is the 3rd problem, the second one is confusing, however this one is similar to the first. I'm going to try and do what you just did.
Here's a more detailed #1
I'm stuck at 5(x^3 - 27)
Try cubing small number until you pass 27. Like 1^3 = 1, 2^3 = 8, 3^3 = ... Like that.
Ok. 3^3 = 27.
now is it 5(x^2 - 3^3)
correct! Now what's your A and B, if (A^3 - B^3) = (A-B)(A^2 + AB + B^2)
a = x b = 3?
Exactly! Now you just plug it into the formula. That's it.
(x - 3)(x^2 + x3 + 3^2)
That is correct.
how would I write x3?
3x. Typically in the business we put the number first.
alright... I have 1 more ima try on my own... I'll mention you when I'm done..
OK
x^3 - 348 is the question.
343*
(x - 7)(x^2 + 7x + 7^2)
Exactly. Now the formula changes if there is a plus between the two cubes, but in this case it is a '-'. Good job!
Holy crap, these are easy! :D
@etenraku1 I read the question wrong. It was x^3 + 343.
Does this just mean the formulas signs get flipped?
Not quite flipped. For differences, only the first is negative. For sums, only the second is negative.
So the final equation would be (x + 7)(x^2 - 7x - 7^2)?
last sign is positive. Otherwise, yes!
Ok, (x+7)(x^2 - 7x + 7^2)
Correct!
Awesome! Thank you so much!
Err Wait.
How do I do it if there is no GCF and the question looks like this: 1331x^3 – 8y^ 3
My pleasure.
Like this. Just think of the GCF as 1.
Same way as the other ones... cool!
Alright, I think that's it. Thanks again!
Join our real-time social learning platform and learn together with your friends!