i want to get a head start on...

Devantè · 2007-09-14 09:22:44

Algebra exercises ... Exercises forum. We didn't spend those old October days twiddling our thumbs for nothing but algebra exercises for no one to post in. There are still plenty of unanswered algebra questions that people have yet to answer.

landof+ · 2007-09-14 18:54:38

So let's say a complicated one like(maybe not so complicated)

Solve in terms of
we can solve in terms of straight away by using

and now

Stop here, I have no idea on how to continue? Can someone solve it for me? It'll be useful for me and lightning if there's an explanation.

Devantè · 2007-09-14 20:58:52

Well, are you looking to solve for x, solve for y, solve for x and y, or simplify?

mathsyperson · 2007-09-14 23:02:28

landof+ wrote:

we can solve
in terms of
straight away by using

You can't necessarily say that. That would only be true if the numerators were also equal.

I don't think the question is doable, actually. To get x in terms of z, you'd need to eliminate y, but the only way to eliminate a variable is to use another equation.
The exception being when a variable eliminates itself during simplification, but that doesn't apply here.

landof+ · 2007-09-14 23:55:07

oh, so that's unsolvable. But it would be if I stated that the denominators were equal, right?

mathsyperson · 2007-09-15 00:41:02

Yup. If you said that, then you've essentially got two simultaneous equations.

In that case, the working you had does work, and in fact you're nearly finished.
You can use your result of 2y=z in the first equation.

Don't bother rearranging it, just leave it as it is, but replace y with z/2.

From there, divide by 25 and you have your answer.

And then, if you wish, you can play around with it a bit more to make it look nicer.

landof+ · 2007-09-15 00:51:08

Thanks! This is very helpful!

lightning · 2007-09-16 04:35:51

??? i dont get it ...... oh but i do know (1y + 1y)
x
(1y + 1y)=4y i think am i right???

mathsyperson · 2007-09-16 05:04:39

Almost.

(1y+1y) x (1y+1y) = 2y x 2y = 4y².
You were right apart from squaring the y.

lightning · 2007-09-16 06:09:51

huh whats up with the tiny 2 why do you have tou put that there?? i don't really get it and how do you square a y?

bossk171 · 2007-09-16 07:08:49

y² is read "y squared"

Interestingly enough there is a thread on that right here

lightning · 2007-09-16 07:27:38

i still don't get it...

bossk171 · 2007-09-16 08:12:18

Have you read that thread? Daniel123's explanation is really good.

lightning · 2007-09-16 08:13:07

i know............ i still don't get it!

bossk171 · 2007-09-16 08:29:48

Well, suppose you want to add a number over and over a bunch of times, like:

2+2+2+2+2+2+2+2

we ca re-write that as:

2*8=16

Now that's much easier. Well, that's multiplication, addition over and over again. Now say we want to multiply over and over again:

3*3*3*3

we write that as:

So, if (5+5) is (2*5) we can say (5*5) is (5²)

So a number, x raised to a power, n is just x times itself n times and is written as:

so x² = x*x

I hope maybe that helps.

Daniel123 · 2007-09-16 08:41:46

The little number means how many times the big number is 'timesed' by itself.

So 3² means 3 times itself twice, so 3 x 3, which equals 9.

3³ means 3 times itself three times, so 3 x 3 x 3 = 27.

What, then, would 4² be?

lightning · 2007-09-16 23:43:57

bossk171 wrote:

Well, suppose you want to add a number over and over a bunch of times, like:
2+2+2+2+2+2+2+2
we ca re-write that as:
2*8=16
Now that's much easier. Well, that's multiplication, addition over and over again. Now say we want to multiply over and over again:
3*3*3*3
we write that as:
So, if (5+5) is (2*5) we can say (5*5) is (5²)
I hope maybe that helps.

Right i get that.... now what next.... so 5*2=10? Am i right? and 4*3+12? Am i right?

landof+ · 2007-09-16 23:45:51

4*3=12

lightning · 2007-09-16 23:47:51

well y'know what i am saying!!! so let's get techniquall..... 3*4=12*4=48???

landof+ · 2007-09-16 23:49:16

nope, but 3^4=3*3*3*3=9*9=9*3*3=27*3=81

lightning · 2007-09-16 23:52:40

what does ^ mean.... maybe 3 over 4 maybe...

landof+ · 2007-09-16 23:54:37

'^' simply means to the power of, mathematically, that is.

lightning · 2007-09-16 23:58:07

i got the power- bruce almighty

landof+ · 2007-09-16 23:59:16

how about Tommy Almighty? Sounds better than luightning almighty...

lightning · 2007-09-17 00:02:51

Yeah Tommo takes the day!! WOOHOO!!!

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