Does anyone know how to solve absolute value equations? I know how to graph them. But I can't solve them. Problems like...

3y=|2x-9|

explain it to me please, my head hurts.

what are you supposed to solve for? looks to me like it's already simplified.

You have to make a t chart. Like a x|y chart thingy.

Like at this site: http://www.purplemath.com/modules/graphabs.htm

but from looking at that site I still don't get it. lol

Ok, it's probably easier to graph it and look at the graph...

Looking at the graph, it seems like X is All real numbers and y is all reals greater than or equal to 0 :D

How come 1/3 isn't inside the |'s?

Oops, I graphed..
noooo keep it there. lol I hate math so much.

I'm stll confused. I don't get how you got the points. Can you show me what the t chart would look like?


3y=|2x-9|

so you devide it all by 3...

y=|2/3x-3| is what I get lol

How come 1/3 isn't inside the |'s?

I just didn't distribute, that's all. It's also..

y = |(2/3)x-3|

I just didn't distribute, that's all. It's also..

y = |(2/3)x-3|
So how would you know the vertext? It's 0, right?

Just because it'll be easier for me to write it, I will....Give me a second.

Just because it'll be easier for me to write it, I will....Give me a second.
Thank you so much. :D

So how would you know the vertext? It's 0, right?

It gives no number for the y part of the vertex, so it's assumed to be 0..

y = |2/3x - 3 | + 0

So your vertex is (3,0). Then just do rise over run w/ your slope and you get the graph. I've never done a T chart for this type of equation, I just look at the graph and can tell where the points are and arent

It gives no number for the y part of the vertex, so it's assumed to be 0..

y = |2/3x - 3 | + 0

So your vertex is (3,0). Then just do rise over run w/ your slope and you get the graph. I've never done a T chart for this type of equation, I just look at the graph and can tell where the points are and arent
Ohh my teacher showed it to us with tcharts. She put that...

y=|2x-5| as a t chart is

X|Y
0 5
2.5 0
4 3

she said from your vertex you choose a number higher and one lower or something that I didn't understand. lol

BAHHHHH. This kind of formula was easy for me to solve in Algebra 2, but alas that was 3 years ago. I still have my notes though...So it wouldn't take long for me to remember. [/dork]

For 2/3 rise over run is go up 2 right 3, right? And that's it?

BAHHHHH. This kind of formula was easy for me to solve in Algebra 2, but alas that was 3 years ago. I still have my notes though...So it wouldn't take long for me to remember. [/dork]
yeah, Im in algebra 2 now. lol

if a negative is outside the problem like..

y= - |-x-2|

that makes all the x's and y's negative right? Except for the vertex, which would be 0?

For 2/3 rise over run is go up 2 right 3, right? And that's it?

Technically yes, but since it's an absolute value equation, you have to go both ways..

if a negative is outside the problem like..

y= - |-x-2|

that makes all the x's and y's negative right? Except for the vertex, which would be 0?

I would distribute my - here, to make it easier..It would then be
y=|x+2|+0. Your vertex is the opposite of 2 and 0 (-2,0)

so up 2 right 3 then down 2 left 3? or what? Ugh I'm sorry to be annoying..

Also in y=|3-x|

the vertex is (1,0) and the rise over run is 3/1?

I would distribute my - here, to make it easier..It would then be
y=|x+2|+0. Your vertex is the opposite of 2 and 0 (-2,0)
So in absolute value it's always the opposite of what's in the |'s? I always thought that whatever was in the |'s was always positive? lol

yeah, Im in algebra 2 now. lol

I'm in precal this year

I'm in precal this year
lol I'll never make it there. I'm a senior right now.

so up 2 right 3 then down 2 left 3? or what? Ugh I'm sorry to be annoying..

Also in y=|3-x|

the vertex is (1,0) and the rise over run is 3/1?

No, this is y = |-x+3|. Your vertex is (-3,0) and your slope is -1

So in absolute value it's always the opposite of what's in the |'s? I always thought that whatever was in the |'s was always positive? lol

Not when you have X's. Unless you know what X is, you can't change any signs.

lol I'll never make it there. I'm a senior right now.

Oh, I'm a junior.

No, this is y = |-x+3|



Not when you have X's. Unless you know what X is, you can't change any signs.

Ok so then it's (-3,0) and 1/1 for slope? so I go up 1 right 1... and then down 1 left 1 and then it'll make a V?

Oh, I'm a junior.

I feel stupid. :drool: :lol:

Instead of using up board space, IM me at AllintheDice07 on AOL or AIM(same difference)

Ok so then it's (-3,0) and 1/1 for slope? so I go up 1 right 1... and then down 1 left 1 and then it'll make a V?

And.. I do this from the vertex, not from (0,0)?

Instead of using up board space, IM me at AllintheDice07 on AOL or AIM(same difference)
I don't have AIM. :\

Ok so then it's (-3,0) and 1/1 for slope? so I go up 1 right 1... and then down 1 left 1 and then it'll make a V?

No, the slope is -1. So you go down one right one. And then from your vertex, down one left one, so it's ^.

And.. I do this from the vertex, not from (0,0)?

Yes, do it from the vertex.

No, the slope is -1. So you go down one right one. And then from your vertex, down one left one, so it's ^.
Oh so you just change the left and the rights? And the first time you graph the slop you don't do it from the vertex, but from (0,0)?

Yes, do it from the vertex.
Both times? lol

I think I get what you're saying about not being able to change the x because you don't know it, finally. lol

y = |-x+3|

No, you use the vertex and only the vertex when graphing an equation like this. The only time you use (0,0) is when (0,0) is your vertex.(example: y=|x|)

y = |-x+3|

No, you use the vertex and only the vertex when graphing an equation like this. The only time you use (0,0) is when (0,0) is your vertex.(example: y=|x|)
oh I always thought x was supposed to be 1x.

So... y =3-1|x+1| is y=2|x+1| which is y=|2x+2| with a vertex of (-2,0| and a slope of 2/1?

oh I always thought x was supposed to be 1x.

Yes, it is..

So... y =3-1|x+1| is y=2|x+1| which is y=|2x+2| with a vertex of (-2,0| and a slope of 2/1?

No. You have to look at the equation closely. There's not a sign between -1 and the absolute value bar. This is understood to be:
y = +3 + (-1|x+1|)
y = -1|x+1|+3
y = |-1x-1|+3
Your vertex is (1,3) and your slope is -1.

Yes, it is..



No. You have to look at the equation closely. There's not a sign between -1 and the absolute value bar. This is understood to be:
y = +3 + (-1|x+1|)
y = -1|x+1|+3
y = |-1x-1|+3
Your vertex is (1,3) and your slope is -1.
ohh so the first number always gets moved to the back of the problem. ^_^

ok this is my last question, in a problem like... 1/2y=|3x-1|-2.. I know you divide the whole problem by 1/2 but do you divide the -2 by 1/2 also?

ok this is my last question, in a problem like... 1/2y=|3x-1|-2.. I know you divide the whole problem by 1/2 but do you divide the -2 by 1/2 also?

You just said that you divide the whole problem by 1/2. So what do you think?