Im not really the one to ask, but this is pretty complicated to me.


You guys know about the 'system of equations' and the 3 ways to solving them, right?...

1.graphing
2.substitution
3.elimination


Well I need some help with substitution..


When its something like this...

y=2x

and

y=3x-2

or

y=x

y=2x-4

What exactly do you do?


Yeah, I took notes on it in school, but its still pretty fuzzy in my head.
Help is much apreciated. =/

Im not really the one to ask, but this is pretty complicated to me.


You guys know about the 'system of equations' and the 3 ways to solving them, right?...

1.graphing
2.substitution
3.elimination


Well I need some help with substitution..


When its something like this...

y=2x

and

y=3x-2

or

y=x

y=2x-4

What exactly do you do?


Yeah, I took notes on it in school, but its still pretty fuzzy in my head.
Help is much apreciated. =/

O my god, this is easy. I can't explain it by typing but what grade are you in? I learn this in 7th grade.

Im not really the one to ask, but this is pretty complicated to me.


You guys know about the 'system of equations' and the 3 ways to solving them, right?...

1.graphing
2.substitution
3.elimination


Well I need some help with substitution..


When its something like this...

y=2x

and

y=3x-2

or

y=x

y=2x-4

What exactly do you do?


Yeah, I took notes on it in school, but its still pretty fuzzy in my head.
Help is much apreciated. =/
What grade you in? Anyway, I just got a 98 in advanced pre-al, so maybe I can help. :P
We just did this shit last week. We'll use this.
y=x

y=2x-4

So take y=x for example, or x=y. Now, if x=y, let's substitute in for the x variable in the second equation. So y=2(y)-4, y=2y - 4, -y = -4, then y=4. Now, to find x, let's substitute again. Go back to y=x. Substitue y for 4, leaving you with 4=x. So your solution is (4,4). Then check:
4=4 (correct)

and

4=2(4)-4
4=8-4
4=4 (correct).

There ya go.

What grade you in? Anyway, I just got a 98 in advanced pre-al, so maybe I can help. :P
We just did this shit last week. We'll use this.
y=x

y=2x-4

So take y=x for example, or x=y. Now, if x=y, let's substitute in for the x variable in the second equation. So y=2(y)-4, y=2y - 4, -y = -4, then y=4. Now, to find x, let's substitute again. Go back to y=x. Substitue y for 4, leaving you with 4=x. So your solution is (4,4). Then check:
4=4 (correct)

and

4=2(4)-4
4=8-4
4=4 (correct).

There ya go.

GOOD JOB man, give your self a high five for just telling him the answer and not letting him figure it out on his own. I lost all respect for your jakuza, I thought you were smarter than this. That equation was just child's play.

Well, im not exactly a fast learner, let alone an average learner.

Well, im not exactly a fast learner, let alone an average learner.

O well, you will learn. I was like that when I was young.

laughingman112, you're seriously losing respect for Jak just because you know something that he doesn't? Just because it is soo easssyyy to you doesn't mean it has to be soo easssyyy to Jak. Grow up, and don't lose respect to people just because of their intelligence. Thats retarded.

Losing respect on someone because they can't figure out an equation; how much more retarded can you be? Tsk.
/warn

Anyways, http://mathforum.org/library/drmath/view/57307.html.
Hope that helps Jak.

GOOD JOB man, give your self a high five for just telling him the answer and not letting him figure it out on his own. I lost all respect for your jakuza, I thought you were smarter than this. That equation was just child's play.Yup. I'm high-fiving myself right now. And chill man. It was ONE problem. I also picked that one out of the 2 because it was easier and wasn't as important. Plus, I know in my case, I can't learn through simple explanations: I need to SEE it happen. I need someone to walk me through a problem before I can see how they can be solved. And no one said he's stupid. Maybe he's just not the best in math. I know a lot of smart people that are horrid at math but great at everything else, and vice-versa.

Yup. I'm high-fiving myself right now. And chill man. It was ONE problem. I also picked that one out of the 2 because it was easier and wasn't as important. Plus, I know in my case, I can't learn through simple explanations: I need to SEE it happen. I need someone to walk me through a problem before I can see how they can be solved. And no one said he's stupid. Maybe he's just not the best in math. I know a lot of smart people that are horrid at math but great at everything else, and vice-versa.

Is he asian?

Is he asian?

...Just when I thought you couldn't be more retarded.

I see that KCBlack already explained it, but I'll try explaining it again in case you still don't understand.

Lets take the first problem. I suggest solving these by substitution because it's the easiest.

y=2x

y=3x-2

You see that Y is 2x, and it's also 3x-2. Therefore, 2x would equal 3x-2. If something equals something, and it equals something else; both those things will equal each other.

For example.
5=3+2
5=1+4
So, 3+2=1+4. Get it?

After you figure out what 'x' is, plug it into one of the equations to find out what 'y' is. Then you should always double check.

Whenever you see a y="equation", and another equation has a 'y' in it, you can substitute that 'y' for the equation. If you still need help, read the section in your book and do some extra problems.

...Just when I thought you couldn't be more retarded.

Durr......

Im not really the one to ask, but this is pretty complicated to me.


You guys know about the 'system of equations' and the 3 ways to solving them, right?...

1.graphing
2.substitution
3.elimination


Well I need some help with substitution..


When its something like this...

y=2x

and

y=3x-2

or

y=x

y=2x-4

What exactly do you do?


Yeah, I took notes on it in school, but its still pretty fuzzy in my head.
Help is much apreciated. =/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
dont you just simplify by combining them.

so if it was
y=x and y=2x-4

then x+2x-4
|
3x-4

oh wait wait

your doing graphs and etc huh?
so there would be two equations....

you dont do nothing then man its just two seperate variables for two different equations

Well thanks, you guys. I think I got the pure concept now. Did 3 on my own just a minute ago. I solved and checked it, and they came out correct. =]

thx to raikun09's 1337 skills in geometry............and those other guys>_>

thx to raikun09's 1337 skills in geometry............and those other guys>_>

This is algebra, my brother. :p

This is algebra, my brother. :pLmao. Glad you got it. I didn't get substitution at first either. Of course, I NEVER pay attention in math and relearn anything I don't get when I get home.

Well thanks, you guys. I think I got the pure concept now. Did 3 on my own just a minute ago. I solved and checked it, and they came out correct. =]

Jakuza, if you don't get subsitution you could use elimination. Which is like the same concept but I found it alot easier.

Jakuza, if you don't get subsitution you could use elimination. Which is like the same concept but I found it alot easier.
Correct me if I'm wrong, but elimination works best if the numbers are the same.

For example. If I got a problem like

y=2x+5
y=3x-5

Then I'd use elimination to do it because it's much easier. But life doesn't always give you problems that are that easy to do. I still suggest using substitution because you'll be using it a lot later on, plus it'll work with almost every problem.

It's been a long time since I've done anything like this so do correct me.

Jakuza, if you don't get subsitution you could use elimination. Which is like the same concept but I found it alot easier.

It depends on the equation. Sometimes its faster an easier to use substitution than elimination, and vice-versa.

Graphing was always easy for me... Infact I laughed when the teacher was explaing y=x and he said when x = 4 than y = 4 and this girl in the class just did not understand why. The teacher was practically yelling at her, and I couldn't really blame him.

The only trouble I had, and still have, is with word problems. When messing with just numbers I can usually crunch it out. But eventually you get into math where you just have to remember about a billion different forumulas, and some formulas only work on certain equations and with certain equations you have to something just a little different...

Math is lame.

hmm i dun rememeber this i think i was sleepin in class that day

The substitution one is piss easy. I can't do elimination though. I did learn, but i wasn't paying attention.

Y=3x-4
Y=2x+5

Find out the X by doing the following:

3x-4=2x+5

3x-2x=5+4

x=9

Now if you substitute the x for 9:

Y=3x-4 = 3(9)-4 = 23
Y=2x+5 = 2(9)+5 = 23

There you go.

The substitution one is piss easy. I can't do elimination though. I did learn, but i wasn't paying attention.

Elimation only works is you can get either same X or same Y. So for example

Y = 2X + 5
Y = 3X - 5
--------------------

(First you need to make the X's equal... the common numerator is 6 hence)

3Y = 6X + 15
2Y = 6X - 10
------------------------

(Now to elimante X we need to make either the top or bottom negative)

3Y = 6X + 15
-2Y = -6X + 10
-------------------------
Y = 25
(The math is simple, just add)

So knowing that (Y = 25) we plug why back in to either Equation

25 = 3X + 15
10 = 3X
X = 3/10

Simple...

Elimation only works is you can get either same X or same Y. So for example

Y = 2X + 5
Y = 3X - 5
--------------------

(First you need to make the X's equal... the common numerator is 6 hence)

3Y = 6X + 15
2Y = 6X - 10
------------------------

(Now to elimante X we need to make either the top or bottom negative)

3Y = 6X + 15
-2Y = -6X + 10
-------------------------
Y = 25
(The math is simple, just add)

So knowing that (Y = 25) we plug why back in to either Equation

25 = 3X + 15
10 = 3X
X = 3/10

Simple...

Hardly. If anything, i un-learned.

What the, how old are you guys? In Singapore we learnt this last year in our 8th Grade, 14 years old. o_O This year all our maths involves algebra lol...

K what you need to do everytime is to make x the subject, that is, to make it alone. First you just make one of the variables alone and substitute it into the other equation, so the equation will only have one variable then you can just bring the numbers over and solve it.

For example:

y = 2x + 5 - first equation (1)
y = 3x - 5 - second equation (2)

Sub (1) into (2)

2x + 5 = 3x - 5
Bring 2x from the left to the right, so it'll become -2X
5 = 3x - 2x - 5
5 = x - 5
Bring -5 to the left so when it moves over the '=' sign it will become +5 right?
10 = x - third equation (3)

Sub (3) into (1)

y = 2(10) - 5
y = 20 - 5
y = 15

Voila solved.

y=2x

and

y=3x-2

y = 2x
y = 3x - 2

Just substitute the first one into the second equation so you'll have
2x = 3x - 2
bring 2x over
0 = x - 2
bring 2 over
x = 2

Donez!


y=x

y=2x-4

y = x
y = 2x - 4

x = 2x - 4
0 = x - 4
x = 4

Have fun with algebra! lol...

What the, how old are you guys? In Singapore we learnt this last year in our 8th Grade, 14 years old. o_O This year all our maths involves algebra lol...

K what you need to do everytime is to make x the subject, that is, to make it alone. First you just make one of the variables alone and substitute it into the other equation, so the equation will only have one variable then you can just bring the numbers over and solve it.

For example:

y = 2x + 5 - first equation (1)
y = 3x - 5 - second equation (2)

Sub (1) into (2)

2x + 5 = 3x - 5
Bring 2x from the left to the right, so it'll become -2X
5 = 3x - 2x - 5
5 = x - 5
Bring -5 to the left so when it moves over the '=' sign it will become +5 right?
10 = x - third equation (3)

Sub (3) into (1)

y = 2(10) - 5
y = 20 - 5
y = 15

Voila solved.



y = 2x
y = 3x - 2

Just substitute the first one into the second equation so you'll have
2x = 3x - 2
bring 2x over
0 = x - 2
bring 2 over
x = 2

Donez!



y = x
y = 2x - 4

x = 2x - 4
0 = x - 4
x = 4

Have fun with algebra! lol...


9th grade, Algebra (H). O_o

His asking for help, give the guy a break. Im pretty sure everybody had ask for help before.

What the, how old are you guys? In Singapore we learnt this last year in our 8th Grade, 14 years old. o_O This year all our maths involves algebra lol...
I'm 8th grade, Advanced Algebra 1. I'm taking Honors Geometry next year in 9th.

As a future engineer, I have to have perfect algerbra skills. I can help with pre-algerbra and algerbra fairly well. I was able to explain algerbra to a friend well and they were not the best at math. They help me with english ,and I help them with math. Anyway, I guess look at the substitution methoed this way.....




2x-3=y
y+5=6

This is just an example so it's not accurate by any means.

My point is when they give you something like

2x-2=y
y-1=x (these are accurate)

They are SAYING that this is what y is equal to. So when they give you two equations they usually will have a relation. They are most likely two lines that intersect. If they give you two equations then they ,in fact, have to be related. So here are some tips if you get something like the above

If you multiply,add,divide,subtract the same thing to both sides of ONE of the equations, you will get the same thing on each side.

here ill prove that too

3=3
3times3=3times3
9=9

I proved it using multiplication!
So how is this usful at all?

back to this

y+2=x-1
I can use those properties to warp this!

y=x-3

but I need one variable eliminated or SUBSTITUTED!

I NEED TWO EQUATIONS TO DO THIS!
If I'm given two I need to use BOTH these methoeds on both to solve for them!!!!!!!!!!!!!!!!!!!!!!!!!!

Does this make sence????

As a future engineer, I have to have perfect algerbra skills. I can help with pre-algerbra and algerbra fairly well. I was able to explain algerbra to a friend well and they were not the best at math. They help me with english ,and I help them with math. Anyway, I guess look at the substitution methoed this way.....




2x-3=y
y+5=6

This is just an example so it's not accurate by any means.

My point is when they give you something like

2x-2=y
y-1=x (these are accurate)

They are SAYING that this is what y is equal to. So when they give you two equations they usually will have a relation. They are most likely two lines that intersect. If they give you two equations then they ,in fact, have to be related. So here are some tips if you get something like the above

If you multiply,add,divide,subtract the same thing to both sides of ONE of the equations, you will get the same thing on each side.

here ill prove that too

3=3
3times3=3times3
9=9

I proved it using multiplication!
So how is this usful at all?

back to this

y+2=x-1
I can use those properties to warp this!

y=x-3

but I need one variable eliminated or SUBSTITUTED!

I NEED TWO EQUATIONS TO DO THIS!
If I'm given two I need to use BOTH these methoeds on both to solve for them!!!!!!!!!!!!!!!!!!!!!!!!!!

Does this make sence????
yea, but can you do algebra II, geometry, Ap stat, or pre cal? I can.

all of you guys are 8th and 9th grade, wow..

man, the last 2 years of school is even more stressful. u know how busy i am these days lol.

all of you guys are 8th and 9th grade, wow..Why, what grade you in?