Algebra

Tidus Blade

Tidus Blade

The Watermelon Man
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Im in year 8, im obviously not using the same system as you guys, but Math is the same everywhere 0.o
Im currently studying Algebra in math class, and it's killing me, i dunno how to expand, simplify, factorize or anything, I got 0% in my last 2 tests, and the exams are coming up, what should I do? Any advise? please
 
Tidus Blade said:
Im in year 8, im obviously not using the same system as you guys, but Math is the same everywhere 0.o
Im currently studying Algebra in math class, and it's killing me, i dunno how to expand, simplify, factorize or anything, I got 0% in my last 2 tests, and the exams are coming up, what should I do? Any advise? please
Click to expand...
Expanding/Breaking the Brackets

(2x + y)(4x + 3)

Let's start off simple. The way I was taught was to remember FOIL (First, Outside, Inside, Last).

Multiply the first to terms [which are 2x and 4x], giving you (2x4) and (x times x), which is 8x-squared. I must apologise, I can't enter a squared symbol.

Multiply the Outside terms [which are 2x and 3], giving you 6x.

So far, we have 8x-squared + 6x

Multiply the Inside terms [which are y and 4x], giving you 4xy.

Now, we have 8x-squared +6x + 4xy

Finally, multiply together the last terms [which are y and 3], giving you 3y.

So, the equation, broken up, is 8x-squared + 6x + 4xy + 3y. Since we have no similar terms, we cannot simplify further and thus the equation is solved. Simple enough?

Let's take another example with a negative sign.

(2x - y)(4x - 3)

Continue to do this in the exact same manner.

[2x times 4x] [2x times -3] [-y times 4x] [-y times -3]
8x-squared -6x -4xy +3y.

You will see the answer is (+3y) - this is because two negatives multiplied together give a positive number. If the two signs are the same (+ times +) or (- times -), then the answer will be positive. If the terms are different (+ times -) or (- times +), then the answer will become negative.

To conclude, every term must be multiplied with every other term, other than the one in the same bracket.

Simplification

When you have broken brackets, sometimes your equation will look something like this:

4x + 5x + 8x +3y + 4m + 9y +2x-squared

To simplify, collect together the terms that are similar. In other words, add together all of the X's, add together all the Y's, the M's and the Squared terms. This would give you...

2x-squared + 4m + 17x + 12y

As with the breaking of the brackets, negative terms are included.

4x - 5x + 8x +3y - 4m + 9y -2x-squared

The equation then becomes:

-2x-squared 7x +12y -4m.

Happy?

Factorisation

There are many ways to do this. If you wouldn't mind expanding on what you are doing in class, I'll be able to help with no problem at all.

 
Wow thanx so much Riku!
Looks much better than how the teacher explains it, the book just shows crap examples!
And about the factorism, it's something like 6x+3+2xy+y - ax+ay-bx-by
Thanx again
+rep, if there was
 
lol ive had this one for like last year too, well anyways, im trying out those and it's working but can u expand (x+5)(x-5) ?
 
Tidus Blade said:
lol ive had this one for like last year too, well anyways, im trying out those and it's working but can u expand (x+5)(x-5) ?
Click to expand...


Ah yes.

(x+5)(x-5)

Multiply [x] and [x]. = x-squared

Multiply [x] and [-5] = -5x

Multiply [5] and [x] = 5x

Multipled [5] and [-5].

Therefore, we have:

x-squared -5x +5x -25

The [-5x] and [+5x] cancel each other out, so the equation is left as:

x-squared - 25.

Done :)
 
OK thanx, thats pretty much how simple it is for you, but since ive never done it before it's really hard XD
Thanx! And you posted all your posts here even before i finish my homeowork, this is the time when i think your awesome ;)
 
Umm ya it's ok, thats my strongest point in algebra but it's still pretty weak, I think i got it buy can you please factorise 6x+3+2xy+y
Sorry if im too much trouble >_<
 
Tidus Blade said:
Umm ya it's ok, thats my strongest point in algebra but it's still pretty weak, I think i got it buy can you please factorise 6x+3+2xy+y
Sorry if im too much trouble >_<
Click to expand...

I hate these ones - you get some pissers.

y +3 + 2x(3 + y)

I'm a little iffy on that one - the single [3] and the single [y] blow it all away from a normal factorisation question. I'm confident with them, but this one has be doubting myself...

Best way to know if it's right is to expand the brackets again and see if the answer matches the question.

[y + 3 +6x + 2xy]

Seems like the closest solution possible to me o_O
 
That sure helped, Thanx alot again!!!!! ^_^;):D
Now I just need to practise, that now i know how to do it.
 
Things you may come up on in factorisation is finding the difference of two squares, quadratics and finding a common factor. Just out of curiosity, have you done this yet?

By the way, you may be asked to expand and simplify brackets and solve the equation, sometimes where there are two sets. Let me use an example.

(3y + 7)(6 +3) = (7y + 3)(5 + 4)
18y + 9y + 42 + 21 = 35y + 28y + 15 + 12
27y + 63 = 63y + 27
63 - 27 = 63y - 27y
36 = 36y
36y = 36
y = 36/36
y = 1

Lmao, most of the time, when you make these up, the equation is a horrible number, but voila! If you haven't gotten as far as this yet, no worries, I just felt like showing off :P
 
It's ok, I know your all much smarter than me, my IQ is pretty low, just read some of my posts around, my most intelligent ones are probably in the Temple of the Ancients where I think alot before posting. Anyways, Im sure that ill come by this soon so it will help! ThX again^_^
 
TSG! stop beating me to the helpings!!!!!!!!! I've taken algebra for 2 years now(I hated doing homework last year....so.....yeah. Teacher said "No geometry, cause you'll fail from not doing homework)) so I'm in it again. way too easy if you ask me. So I'll help*relieves TSG of duty*
 
lol, smart nerd getting pwned!
Anyways, im sure ill be wetting my pants on calculus or however u spell it
 
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