Sci I need your help. Self teaching A-level maths and this may sound like a dumb question but does it matter what way round your simplified equation turns out to be?
3ab-3ac+3a-7ab+5ac
I came to the answer -4ab+2ac+3a
However, in the answer book they've written it as 3a +2ac-4ab
Is my answer still correct, or does having a negative at the front make it wrong. aiming for an A star and having looked at maths in years, and i don't want to go into an exam and lose marks on something little like this. Thanks
>>8019138
your answer is the same as the one in the book, where the negative term is doesn't change anything since addition commutes (order doesn't matter)
no one would dock you marks for this
You couldve literally plugged n chugged both answers and get the answer to your question quicker than posting a thread about it on /sci/
>>8019155
I'm not looking to save time though, slow and steady wins the race. I'd rather spend 5 minutes getting solid advice from more qualified people, with explanation, than trial and error without being able to explain it and losing marks on an exam,
>>8019165
Well, you should at least remember that addition is commutative.
[eqn]\begin{aligned}
a + b &= b + a \\
a - b &= a + (-b) = -b + a \\
\end{aligned}[/eqn]
>>8019172
Thanks
I just had this question though :
-3x^2 - 5x + 2 + 3x^2 + 2x - 7x -12
i got
= 3x^2 + 3x^2 - 5x - 7x + 2 -12
= 6x^2 - -2x - 10
The answer however is:
6x^2 - 12x - 10
Where have I gone wrong?
>>8019201
sorry, didn't mean the negative sign on the -3x^2 at the begging. Question is 3x^2 - 5x + 2 + 3x^2 + 2x - 7x -12
>>8019214
So, a negative number multiplied by another negative number is a positive number.
However, a negative number added to another negative number is negative.
I'm sure you understand that adding a negative number is equivalent to subtracting a positive number.
>>8019221
Yes, i get that, I just don't understand how
= 3x^2 + 3x^2 - 5x - 7x + 2 -12
=6x^2 - 12x - 10
It's the - 5x - 7x = -12x what through me, as i got -2x
>>8019232
I'll break it down.
Ignore the x's for now. If I asked you what 5 + 7 is, you'd (hopefully) answer back with 12. Now, what if I multiplied (5 + 7) by -1?
If 5 + 7 = 12, then
-1(5 + 7) = -1(12), right?
>>8019236
yes but how does 5-7 = 12
I'm not trying to sound like a retard, even though i do
This is b8
>>8019242
not bait
>>8019241
Alright, I have no idea what the problem is. Maybe it'd be better of you explained how -5 -7 became 5 - 7.
>>8019264
i dont know.
i got it (maybe)
−5x−7x
=−5x−7x
=−5x+−7x
but why does the - turn to a + ?
>>8019264
OH SHIT
-5x-7x = -12 because they're both negative
have i just been this retarded
have i just spent an hour stuck on a question because i didnt know it was a negative. fml
>>8019270
Nonono, you've got it exactly. It's a negative 7 and a negative 5. I was trying to guide you through the steps by showing an analogous situation with positive numbers. -7 - 5 is indeed -12.
>>8019276
don't beat yourself over the silly mistakes or you'll kill yourself over the big ones
Yes the answer is still correct.
a(3+2c-4b) is actually the simplest form with integer coefficients.
Having the negative on the correct coefficient is the most important thing. Thats because -4+4=0 is the same as 4-4=0 and 4=4
>>8019138
Wow britcucks sure are dumb. How the fuck do you not know addition is commutative?
>>8019326
Because I turned into a dude weed and my father who had a PhD in physics basically kicked the fuck outta me and told me to sort my shit out
As that is what I'm doing
>>8019352
If your A Levels are in a month and your level of math is still at the stage where you literally can't tell that addition is commutative or how to juggle +- signs, I got pretty bad news for you senpai.
>Because I turned into a dude weed and my father who had a PhD in physics basically kicked the fuck outta me and told me to sort my shit out
>As that is what I'm doing
>That sentence composition
Holy shit man, weed must've wrecked your brain hard. You turned into a dude weed? What the fuck?
>>8019904
very hard senpai
Sitting all exams next year as well bro
havent smoked a zoot in 3 weeks and im actually starting to pick this shit up now.
fucking weed
>>8019138
Ey mate, I am self-studying as well, trust me here, if you don't have a tutor, and are getting caught up on this stuff, an A* is not gonna happen.
Just wait until advanced initgration and stats 2 or mechanics 2.
>>8020162
Also, I am this guy
>>8020180
And you want to be finishing at least a book every 6 months my friend, so you need to be finished with pure maths one by now if you are writing next November.
This is the pace I keep up just to score realisticly Bs.
You understand that an A* in A levels maths is a massive statistical improbability with your current position?
Did you do GCSE or skip like I did?
>>8020180
My dad has a PhD in physics, so i can ask him to tutor me, however, i will only do that when i get onto the harder stuff/a2.
If i went to him and asked him about this question in the OP, and told him i'd been stuck on it for an hour he'd disown me. Same as my brother
I got an A/A* in GCSE can't remember. I've always had the potential, I've just been my biggest hindrance. I have a friend who's doing a degree in maths currently, and he offered to help me in any way.
I've work 4/5 days a week, and i'm dropping that down to 3 full days a week (dad told me to) so I'd spend four days a week (like 8-10) hours just doing maths.
And then i may chose to enrol on another A-level course, such as Chemistry / Physics.
>>8020180
The two exams I've take are both statistics. So c-1/4 with S1/2
>>8020202
>>8020204
You are writing the same exams as me..
I take Maths, Biology, and Geography, and only dropped my other 4 because I either aced or had no chance without a teacher after AS level.
I work 7 days a week, 8-10 hours, and I am going to be very happy walking ou with a B, having scored top of my class my whole life.
This is a totally different ballgame to GCSE anon, I had friends who A*ed all their subjects end up totally failing AS...
Work much harder than you are now, and generally Unis will want 3 A levels, which in sciences cources need to be a BBA achievement level minimum...
>>8020218
I Have an A* In History, B in Biology and A in Computer Science at A-level.
I can always take a another science, however to get into a foundation year i literally need two A-Levels, with at least a B in maths.
So while I only need a B, I want to aim for an A*, in case i decide to go to a better uni / take another science a level
>>8019232
The moment that I finally understood what you are trying to, was when I realized that there is no difference between minus as an operator and minus as a "prefix" for the number. Just write all numbers in paranthesis with the minus if there is one in front of them, and connect the paranthesis with plus.
>= 3x^2 + 3x^2 - 5x - 7x + 2 - 12
Becomes : (3x^2) + (3x^2) + (-5x) + (-7x) + (2) + (-12)
Now you just add the ones up that you can, ie. take
(-5x) + (-7x). The (-5x) is 5x to the left of zero and now you move further left by another 7x. You are now 12x to the left of zero, hence your result is (-12x).
>>8020229
So with all of these, you are really rewriting your Maths? and expecting to take another A level, putting you up to 5? making at least 2 unnessasary?
And with a computer science A you are worried about basic algebra??
>>8019201
You're doing 5x-7x and ignoring the fact that 5x is a negative number. -5x-7x=-12x
>>8019286
I'd be worried if I was you. Going for aerospace engineering when even basic arithmetic is a difficulty? You need to practice a lot more and make this kind of stuff second nature before going into anything harder.
>>8020232
Computer science a level is like using forumlas in excel lol for a start
I need a maths qualification to get into a non retard uni to study aerospace
But ideally I'd get an A/A* IN maths, and start a physics A-level, and study some sort of aerospace w/space technology,
>>8019165
holy moly, this guy
>>8019286
I don't want to be mean but you will fail the shit out of any engineering that you do unless you spend at least two years grinding away on your math skills first.
>>8019138
Why didn't you learn basic algebra at GCSE?. This is A-Level material now?.
That being said... more practice is what you need.
>>8020325
It is not A level at all, which is why I am deeply confused about he passed any other A levels with this kind of gap.
>>8020188
>skip GCSE Maths
What da fug
>>8020325
Because i haven't done any maths in two years and smoked a lotta weed
Right now I'm having trouble on another question.
(r^2 + 3t^2 + 9) - (2r^2 + 3t^2 - 4)
I got -1r^2 + 6t^2 + 5
but the answer in the book is
13 - r^ 2
>>8020365
If he is getting passes in A-Levels with mathematical content and the OP's skill level in algebra is what it is, then I have sore misgivings about examination standards these days.
>>8020396
Ah shit, do you have to distribuate the negative sign?
>>8020396
>(r^2 + 3t^2 + 9) - (2r^2 + 3t^2 - 4)
remove brackets and simplify.
>>8020396
You should probably write every operation out separately, friendly advice for you dense fag
Group the terms (r^2 + - 2r^2), (3t^2 - 3t^2) (9 - - 4) then you'll get the right answer
How did you even pass GCSEs without knowing basic shit like this
>>8020418
I knew the basic shit, like 5 years ago...And my memory has gone to shit. Like I'll walk into a room and forget what i needed to get. But, my memory getting a lot better
Dude, you are trolling surely?.
>>8020432
I wish i was...
>>8020427
Just go through bitesize at KS3 or start Khan academy
>>8020442
That's what is it. It's not even the maths, Like I can work out sums pretty quick etc, it's just all the rules. I've been slowly catching up on them though, and once i relearn the KS3 basics I'll be fine.
>>8020446
Okay, there is a pretty cheap alternative. Try fleabay and pick up a copy of GCSE Mathematics by Greer for < £3. I used that in 1987. All basic algebra rules are in there and explained clearly.
>>8020463
Thanks bro
>>8020369
Switched systems into CIE from a steiner school, so walked into AS with a mix of random shit. same in all subjects.
Topped my class and school, faggots had to eat some words.
Anyway, think i' m pretty much there with algebra now. Just gotta practice the shit a bit more in order to embed it in me head
>>8020591
wait are you the guy doing CIE
you know you're probably gonna get slain right
>>8020653
Nah, I'm not "dumb" I've just forgotten.
I'm a very fast learner, however i have smoked a lot of weed. 10/15 zoots a day for 3 years. The last 3 weeks ive been studying and i just haven't been able to concentrate, however my head has cleared and i can actually remember what im doing and apply it.
Only thing gunna slay me is dat pussy
One last thing can someone confirm if this is right?
10x^5 / 2x^-3
=10 / 2 = 5
= X^5 - x^-3 = X8 (Does 5 - -3 = 8 because two negatives?
So is 5x^8 correct?
this whole fucking thread
>>8020682
Yes
>>8019138
Do you have Skype or Kik, OP? I'm self studying further maths whilst doing in my sixth form college maths, computer science and physics, would love to talk to you about how you're doing and maybe help you out?
>>8020836
This guy is a known phisher, ignore his scams
>>8020836
Will sign up now
MathsRetard69
>>8020852
>anon is a known phisher
is this a bait
Last question i swear guys
2a^3 / 3a^2 x 6a^5
it equals 20 - 6x
there is no fookin x
>>8021192
oh wait was reading wrong answer ignore me
>>8020662
>bad at math
>still wants to do CIE
Might as well sign up for Singapore A levels while your at it senpai.
