Answer:
B, if you have any questions how I did anything, or questions in general, let me know.
Explanation:
First you want to make sure you understand distributing. Just using variables I will show how to districute a similar expression.
(a - b)(c + d - e)
There are several ways to think of it. you could treat (a-b) as one term and distribute it into c + d - e like this. pretend (a- b) = x
x(c + d - e) = cx + dx - ex = c(a-b) + d(a-b) - e(a-b)
Then just do a bit more distributing, then combine like terms.
You could instead make (c + d - e) a single term and distribute that into (a-b)
I prefer doing it all in one step, similar to FOIL-ing. Take the first term of one of the expression in parenthesis and distribute it, then move on to the second and so on.
so with (a - b)(c + d - e) I would start with a and distribute that into (c + d - e) and get ac + ad - ae then do the same to -b and get -bc - bd + be then you add the two parts together. ac + ad - ae + -bc - bd + be = ac + ad - ae -bc - bd + be. Then you would combine like terms. Let me know if you need help with that.
Anyway, now for your problem. Keep in mind you can use any of the methods.
(2x^2 - 3y^2)(4x^4 + 6x^2y^2 + 9y^4)
First distribute 2x^2 into (4x^4 + 6x^2y^2 + 9y^4)
8x^6 + 12x^4y^2 + 18x^2y^4
Next distribute -3y^2 into (4x^4 + 6x^2y^2 + 9y^4)
-12x^4y^2 - 18x^2y^4 - 27y^6
Now add the two together.
8x^6 + 12x^4y^2 + 18x^2y^4 + -12x^4y^2 - 18x^2y^4 - 27y^6 = 8x^6 + 12x^4y^2 + 18x^2y^4 - 12x^4y^2 - 18x^2y^4 - 27y^6
Finally combine like terms.
12x^4y^2 - 12x^4y^2 = 0
18x^2y^4 - 18x^2y^4 = 0
So that leaves us with 8x^6 - 27y^6
B is the only answer that works, none of the other 3 can be simplified or adjusted to make them equal what we need, so B is the only right answer.
If you have any questions though let me know.