@Obliv Figures that when I ask for help I'm kicked out where I got the question.
Anyways, I've got another one. Its involving finding difference, but as I've learned its a trick. I got this far with the problem, the invisible 1 changed some of the signs. $-2d^3 + 6d - 9 + 7d^2 - 5d - 13$ Originally it was $(-2d^3 + 6d - 9) - (-7d^2 + 5d + 13)$. I got this far alone and want to confirm my thought process, so I'd like a second opinion.
the core principle with polynomial arithmetic is recognizing what the monomials are. in one variable d, that's powers of d, in a multivariable setting it is subtler.
the addition is defined so that you can "collect" like monomials and "add their coefficients." but none of this is well-posed without a lot of background understanding. "6a^4 b^4 +(8a^4 b^4 - 9b)" is not in anyway disqualified as an answer to an ill-formed question that just asks you to "add" those polynomials
same reason that "31 - 26/2" is a perfectly good response to "what's 31 - 26/2." specifying the form of an answer to the question is 99% of the question.
Were I to give a similar question to my students, the instruction would likely be something like "Simplify the following polynomial expression so that there is only one of any term of the form $Ca^m b^n$, where $C$ is a real number, and $m$ and $n$ are natural numbers."
I would need to word smith that a bit more, as it is a bit hard to grok, but I think that the general intention of the question is to get you to "combine like terms".
In other news, it is currently 77°F inside. Is it time to turn on the AC?
@YourLordJoyBoy Yeah so you basically distribute the minus sign. Also the first parentheses is just another implicit $1(...)$ so we just have $-2d^3+6d-9-1(-7d^2+5d+13)=-2d^3+6d-9+(-1)(-7)d^2+(-1)(5)d+(-1)(13) = -2d^3+6d-9+7d^2-5d-13)$
Actually, I would probably give the instruction "Rewrite the polynomial in standard form," where "standard form" is something that would have been discussed previously in class---roughly, write the terms in order of decreasing degree, and if two terms have the same degree, write them in lexicographical order; no two terms should contain precisely the same combination of variables, i.e. collect "like terms").
@XanderHenderson I believe that was in standard form, the final answer I mean. And now I'm doing a similar one, and trying to combine $9/7z with 15z$. Other than that the problem is cake.
For me however, it heavily impacted meh life during hard times.
And you're still Usopp to me XD
But seriously its one of those things, you're going through crap times irl and something crazy pops up that proves to be a fantastic escape from the reality bs in your life.
