Graphing Equations, HELP!

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Hello,

My name is Christina. I found this site tonight, and I'm glad I did! I need some help. I've been trying for 5 days to understand this one page in my math book. It is graphing equations. I understand pretty well how to graph an equation that is like this. 3x - 4 = y
Here are the questions I'm having trouble with. I only have 1 1/2 months to get my GED so I really need to start moving along with this math! Any help would be appreciated. Thank you. :)

2x + y = 5

x - 2y = 1

-2y = 4x

-x = y + 2
 
artistic_c said:
Hello,

My name is Christina. I found this site tonight, and I'm glad I did! I need some help. I've been trying for 5 days to understand this one page in my math book. It is graphing equations. I understand pretty well how to graph an equation that is like this. 3x - 4 = y
Here are the questions I'm having trouble with. I only have 1 1/2 months to get my GED so I really need to start moving along with this math! Any help would be appreciated. Thank you. :)

2x + y = 5

x - 2y = 1

-2y = 4x

-x = y + 2
Click to expand...


Solve for y

2x + y = 5

Subtract 2x from both sides.

This gives you y = -2x+5
 
Hello,

My name is Christina. I found this site tonight, and I'm glad I did! I need some help. I've been trying for 5 days to understand this one page in my math book. It is graphing equations. I understand pretty well how to graph an equation that is like this. 3x - 4 = y
Here are the questions I'm having trouble with. I only have 1 1/2 months to get my GED so I really need to start moving along with this math! Any help would be appreciated. Thank you.

2x + y = 5

x - 2y = 1

-2y = 4x

-x = y + 2
***********************************************************

If you write your equations in slope-intercept form, you can easily graph them.
The slope-intercept form of a line is: y = mx + b

The b (the constant term) tells you where the graph crosses the y-axis when the x-coordinate is 0.

The m (the coefficient of x) is the slope of the line.

Take the equation 2x + y = 5 and solve for y.

y = -2x + 5 which gives you a y-intercept of (0, 5) and a slope of -2.

Plot the intercept first. From there, find a second point by using the slope of -2. Remember that the slope of a line is the change in the y-coordinates divided by the change in the x-coordinates (m = y/x). From the point (0, 5) move over 1 in the positive x direction and down 2 in the negative y direction. The next point would be at (1, 3). Connect those two points and you will have your graph.

Solve your other equations in a similar manner.
 
Since you're simply "graphing" the darn thing,
why not simply get both intercepts?
2x + y = 5
if x=0, y = 5
if y=0, x = 5/2
join the 2 points (0,5) and (5/2,0)
 
Thank you everyone. I understand -2x + 5 = y but I still need some help with the other ones.
 
The third equation does not have a constant, the line will pass through the orgin, solve for y to find the slope.

When denis is telling you to find the intercepts, what he is telling you is to substitute zero for x then solve for y AND substitute zero for y then solve for x TO RECIEVE TWO ORDERED PAIRS. The resulting ordered pairs, when graphed will be located on the coordinate axis.

for example 2x+y=5

FIRST ORDERED PAIR (substitute zero for the variable x)

2x+y=5
2(0)+y=5
0+y=5
x=0 and y=5
(0,5)

SECOND ORDERED PAIR (substitue zero for the variable y)

2x+y=5
2x+(0)=5
2x=5
x=5/2
x=5/2 and y=0
(5/2,0)

Substituting zero, then solving will work for all linear gbraphing problems without any special exceptions. just remember:

1) SUBSTITUTE (ZERO)
2) SOLVE

Can't go wrong with that. I hope this helps.
 
I can solve the ones that end in =y. Like for example, I know how to solve 6 - 3x = y
I've only been doing algebra for about 2 weeks. I don't know the terminology that is used. I just need help with these. Thank you.

x - 2y = 1

-2y = 4x

-x = y + 2
 
artistic_c said:
I can solve the ones that end in =y. Like for example, I know how to solve 6 - 3x = y
I've only been doing algebra for about 2 weeks. I don't know the terminology that is used. I just need help with these. Thank you.
x - 2y = 1
-2y = 4x
-x = y + 2
Click to expand...
Christina, if you can't do these after what we've told you (particularly zerodegrees),
then there's not much we can do here: not a classroom.
Do you have a math teacher?
WHY were you given these if you don't know how to solve?
 
Denis said:
artistic_c said:
I can solve the ones that end in =y. Like for example, I know how to solve 6 - 3x = y
I've only been doing algebra for about 2 weeks. I don't know the terminology that is used. I just need help with these. Thank you.
x - 2y = 1
-2y = 4x
-x = y + 2
Click to expand...
Christina, if you can't do these after what we've told you (particularly zerodegrees),
then there's not much we can do here: not a classroom.
Do you have a math teacher?
WHY were you given these if you don't know how to solve?
Click to expand...

I can solve the problems if they are explained correctly to me. I have a GED instructor, but she doesn't have time to work with every student one on one. And as far as the equations go, I am working out of a GED book, so I have to be pretty independent.
 
Ok, i get it.....

You think since the format is different, the technique must be different as well.

To graph a linear equation you need:


1) The letter/variable x
2) The letter/variable y
3) And equal sign (gasp!)
4) A number, other wise known as a constant.


Now read the fine print....


IT DOESN'T MATTER WHAT ORDER THEY ARE IN!!!!

Also, just a guess, but i think you are trying to visualize the problem. Since the problem is written in many different forms, you think there are many different techniques to answer the problems.

There aren't.

There are about 5 to 6 techniques TOTAL in algebra 1

1) Substitution
2) Solving equations
3) Distributing
4) Graphing coordinates
5) Factoring
6) Who cares anyway. You get the point.

All these math problems are a combination of these techniques.

If you have the aforementioned situation (you know, x, y, =, and a number) x and y are working together (that's why they they are being added together). Your job is to describe the relationship between the two variables, or how exactly do they work together.

I know, you want to say something like: "but x and y are on different sidees of the equal sign!!!!"

Yeah, but how does that change anything? Through the miracle of addition and subtraction., i can move the variables around to whichever side of the equal sign i want.

Example:

2x+y=5
** -y -y
-----------
2x=5-y TA-DA!


I can still use the techniques of substituting (zero), solving for the one variable that's left over, that gives me one relationship that i can graph (the ordered pair)

Another guess: you really haven't tried to follow the steps that was outlined. Must be a trust issue.

Take ANY of those equations, pick a variable (x or y) and substitute zero.

That variable will disappear MAGICALLY!!! Now you will be left with 1 variable, an equal sign and a number.

My hope is when you reach this situation you can solve for the variable you did not substitute for.

VIOLA! You have one value for x and one value for y, and one of the values will be zero!!!!!!

Now actually try this on you paper several times instead of thinking it out. In my experiences, the more you think about the problems, the more confusing it gets. There are not a million rules for algebra, just a couple. If you try doing instead of thinking, the results will pan out much better for you.

and remember....

SUBSTITUTE ZERO!!!!! :idea:
 
I understand it!

I woke up this morning and all of a sudden, I figured out everything! I couldn't believe it. I wasn't looking at it like an equation. Thanks for your help everyone. :)


zerodegrees: You are exactly right. That is what I thought!
 
Re: I understand it!

artistic_c said:
I woke up this morning and all of a sudden, I figured out everything! I couldn't believe it. I wasn't looking at it like an equation. Thanks for your help everyone. :)
Click to expand...
Ahhh...way to go, Christina !
Btw, did you also kick yourself :?: (I often did!)
 
Re: I understand it!

Denis said:
artistic_c said:
I woke up this morning and all of a sudden, I figured out everything! I couldn't believe it. I wasn't looking at it like an equation. Thanks for your help everyone. :)
Click to expand...
Ahhh...way to go, Christina !
Btw, did you also kick yourself :?: (I often did!)
Click to expand...

Yeah. I'm like, " It is so easy. How could I not know it after several days!?!?" lol Thanks for your help. :)
 
Re: but wait....

zerodegrees said:
Did you try the Mr. Pibb and Red Vines? 8-)
Click to expand...

? I don't know. lol I just woke up one morning and I could figure it all out. :)
 
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