Anybody here good at Algebra?

[BobbyChalfont]

How would I go about simplifying these?

1) 4x(*) + xy - y(*) - 3yz - 2x(*)
2) pq - 3qp + p(*) - 2pq
3) m(*) +4m +3m(*) -2m

Note: (*) stands for squared. I couldn't work out how to do the little number two. so it's 4x squared plus xy minus y squared etc....

 

[Avery]

Not that it matters, but I believe proper notation when you can't do superscript is with an upwards arrow: 4x^2.

=p

 

[The Gardener]

Quadratic equations.

http://www.mathcracker.com/quadratic_eq ... solver.php

 

[ali777]

How would I go about simplifying these?

1) 4x(*) + xy - y(*) - 3yz - 2x(*)
2) pq - 3qp + p(*) - 2pq
3) m(*) +4m +3m(*) -2m

Note: (*) stands for squared. I couldn't work out how to do the little number two. so it's 4x squared plus xy minus y squared etc....

1) x^2(4-2)+y(x-y-3z)
leads to: 2x^2+y(x-y-3z)

2) pq(1-3-2)+p^2
-4pq+p^2
p(p-4q)

3)m(m+4+3m-2)
m[m(1+3)+2]
m(4m+2) => you can take the 2 out as well
2m(2m+1)

 

[ghg]

You should've asked me 5 years ago. I'm one of those ppl who learns this stuff and then forgets it in a heartbeat after the exam.

 

[barcafan]

You should've asked me 5 years ago. I'm one of those ppl who learns this stuff and then forgets it in a heartbeat after the exam.

So i guess it's safe to say you never truly 'learned' it.

Thank god for my grade 11/12 calculas teacher who actually did some theory work with us, or else i'd just forget everything because the whole math ciriculum is based solely on memorization which is the most retarded way to teach math.

 

[BlahBlah12]

How would I go about simplifying these?

1) 4x(*) + xy - y(*) - 3yz - 2x(*)
2) pq - 3qp + p(*) - 2pq
3) m(*) +4m +3m(*) -2m

Note: (*) stands for squared. I couldn't work out how to do the little number two. so it's 4x squared plus xy minus y squared etc....

1) x^2(4-2)+y(x-y-3z)
leads to: 2x^2+y(x-y-3z)

2) pq(1-3-2)+p^2
-4pq+p^2
p(p-4q)

3)m(m+4+3m-2)
m[m(1+3)+2]
m(4m+2) => you can take the 2 out as well
2m(2m+1)

yup.
man algebra was kinda fun...i miss it-
bobby, how old are you that youre taking algebra 1? i think i was a freshman in high school when i took that

 

[BobbyChalfont]

I'm 24 and did all this when I was 15/16 years old, but like GHG I've forgotten it all. I had it pretty much down as a teenager, but since then I haven't really used it, despite going to university and graduating in a Science (Biology to be specific).

I will say one thing, I used to soak this kind of stuff up like a sponge as a kid, but as a 24 year old, it's really hard to re-learn. I'm trying to self-teach at the moment, which is why I posted it here, to check my answers.

 

[Ian Curtis]

I thought this would be some challenge :thumbdown2:
Those are only simplifying expressions.

 

[BlahBlah12]

what are u doing now that u actually need to simplify algebraic expressions?

 

[BobbyChalfont]

what are u doing now that u actually need to simplify algebraic expressions?

Nothing, really. It's just that I recently read a Biological Science research paper with some complex algebra in it and it seemed like complete gibberish to me, so I thought I'd re-teach myself and start from the ground up as it were.

Are there any practical places where you'd need to simplify algebraic expressions in the real world? I can't really think of any...

 

[ali777]

what are u doing now that u actually need to simplify algebraic expressions?

Nothing, really. It's just that I recently read a Biological Science research paper with some complex algebra in it and it seemed like complete gibberish to me, so I thought I'd re-teach myself and start from the ground up as it were.

Are there any practical places where you'd need to simplify algebraic expressions in the real world? I can't really think of any...

Most scientific papers give statistical analyses of test results. In a way, all you need is statistics. Especially in medicine and biology everything is statistics. Even when we talk about hairloss, we play with statistics. We know finasteride has about 80% success rate, so we take the pills with the hope that we are within the 80%.

Look at things like distribution, mean and median average, standard deviation, variance, etc.

If you have an understanding for maths, you can learn statistics in no time.

I'm 24 and did all this when I was 15/16 years old, but like GHG I've forgotten it all. I had it pretty much down as a teenager, but since then I haven't really used it, despite going to university and graduating in a Science (Biology to be specific).

I will say one thing, I used to soak this kind of stuff up like a sponge as a kid, but as a 24 year old, it's really hard to re-learn. I'm trying to self-teach at the moment, which is why I posted it here, to check my answers.

TBH, in my 20s, I struggled with learning as well. I wouldn't understand most things I read.

The way I see is that we grow up learning lots of theories and equations, but we don't really understand where those theories fit in real life. At one point everything reverses. We get a better picture of the world and we know where everything fits, but we don't remember the equations we learnt as kids.

I'm actually very satisfied with the way my brain is functioning right now. I have a good understanding of IT in general, I have gaps in my knowledge but they are easy to fill in, if needed. It took me long time to get to this point...

Kids in general do not respect experience, they think being academically successful makes them special but life is much more than a few exams. I appreciate experience much more now.

 

[CCS]

I don't forget any of the math I learn. But when I memorized the divergence theorem in multivariable calculus, I don't fully know it now. I only remember 1/3 of it, which is not enough to use it. But that is something I crammed before the exam. Anything I actually did the homework for, and read the chapter on, I remember just fine. Ask me again in 5 years. Knowing me, though, I'll work my way through some books again later.

Funny though. Why do I need to know this stuff? There are many engineering applications, but most can be done with just the basics.

Algebra problem:

A boat goes upstream 5 miles at a constant water speed in 30 minutes. It then comes back down stream at the same water speed and reaches the starting point in 20 minutes. How fast was the boat moving, and how fast was the water moving?

Well, we must assume the water stays the same speed, and that the river is not wider in parts. I could set up two equations and two unknows with x = water speed and y = boat speed, but why use the algebra when I could put a stick in the water and time it. Maybe because the water near the back is moving slower than the water in the middle. But then we would have to know what part of the river the boat was in.

I could also give you some calculus problems, and then solve them with simple geometry. In order to give you a problem tough enough that you'd have to use calculus, I'd have to give you the equation of surface, which no one would even know in real life. So if you measured the surface, it would be smarter again to use geometry, though the calculus would be a good backup error check.

 

[Bryan]

CCS, can you give us that fascinating logical puzzle again which you described to us a few months ago? I was trying to tell a friend about it, but I couldn't remember how it went. It has something to do with two guys who are given some details about an unknown number (or something), and they try to figure out what it is. Taking turns, the first one says he doesn't know the identity of the number (or whatever it is they were guessing); then the other says the same thing; then the first one says, "I know the number!" You remember the puzzle I'm talking about, right? Can you repeat that one for us again?

 

[CCS]

CCS, can you give us that fascinating logical puzzle again which you described to us a few months ago? I was trying to tell a friend about it, but I couldn't remember how it went. It has something to do with two guys who are given some details about an unknown number (or something), and they try to figure out what it is. Taking turns, the first one says he doesn't know the identity of the number (or whatever it is they were guessing); then the other says the same thing; then the first one says, "I know the number!" You remember the puzzle I'm talking about, right? Can you repeat that one for us again?

That problem was given to me at a Putnam Exam prep class. I rarely solved any of their problems, but got a "pass" for showing up and trying. (passed the class, not the test). I copied the problem on to here. I don't remember all of it or the details. Buy the number of times it took each of them to say if they knew what the other was thinking, and some other details, we know which number it was. There were two questions, each leading to different numbers. Sorry I can't help. I thought you guys took a much better stab at it than I could have done, even though you did not get the answer I was told was the answer.

 

[Bryan]

Damn! I'm going nuts trying to remember that problem!

 

[BobbyChalfont]

Here's a few more for you mathematics, then.

1) A = h(a+b) / 2

a) find h when A=40, a=10 and b=6
b) find a when A=36, h=9 and b=6

2) The final velocity (v) of a body is related to the initial velocity (u), the constant acceleration (a) and the distance (s) for which the acceleration acts, by the formula:
v^2 = u^2 + 2as

a)If a body starts with a velocity of 10m/s and is accelerated at 2m/s^2 for a distance of 11m find the value of v^2 and hence find the final velocity.
b) Find the value of s when v = 30m/s, u=5m/s and a=1om/s^2.
c) Find the value of u when v=20m/s, a=2m/s^2 and s=10m

 

[ali777]

Here's a few more for you mathematics, then.

1) A = h(a+b) / 2

a) find h when A=40, a=10 and b=6
b) find a when A=36, h=9 and b=6

2) The final velocity (v) of a body is related to the initial velocity (u), the constant acceleration (a) and the distance (s) for which the acceleration acts, by the formula:
v^2 = u^2 + 2as

a)If a body starts with a velocity of 10m/s and is accelerated at 2m/s^2 for a distance of 11m find the value of v^2 and hence find the final velocity.
b) Find the value of s when v = 30m/s, u=5m/s and a=1om/s^2.
c) Find the value of u when v=20m/s, a=2m/s^2 and s=10m

why don't you try to solve them by yourself first, and then ask us what you don't understand???

These are simple questions, I can solve them without using pen and paper but I can't give you the answers straight away. That would defeat the point of you learning maths.

PS: can you solve the problem in my avatar :whistle:

 

[BobbyChalfont]

Don't worry Ali, I have been working on the problems myself! I'm not foolish enough to expect to learn algebra by having other people tell me the answers!

From your avatar, signiture and location, I would hazard the guess that you yourself are quite profficient with Mathematics. May I ask what you do for a living and how far you took Maths in education? (A-Levels, degree level?)

Perhaps you yourself have some interesting Mathematical problems for the good people of gourmetstylewellness.com to solve!!

PS: "I can solve them without using pen and paper" - show off :tongue:

 

[Bryan]

That would defeat the point of you learning maths.

May I ask what you do for a living and how far you took Maths in education?

May I ask why British people (and non-British people who have been living there for a while) insist on using the word "maths" (plural) in writing things like the previous examples? :dunno:

The word "math" is clearly an abbreviation for "mathematics", so where does this urge to make it plural by adding an "s" to the end come from? To American ears, saying "the point of you learning maths" sounds as odd and peculiar as saying "the point of you learning grammars". See what I mean? :mrgreen: