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#1 2012-07-27 05:06:28

SlowlyFading
Member
Registered: 2012-06-12
Posts: 149

Help me Find Two Points from this Problem and Show your Work!

I need help finding 2 points from these equations. I tried solving them myself (My work is below) but it was wrong. So I need the correct answers and please show your work. Thank you!

I need help with this one: 4x + 3y = -15

My work for it:
4x + 3y = -15
4(0) + 3y = -15
0 + 3y = -15
3y = -15

-15/3
(0, -5)

4x + 3y = -15
4x + 3(0) = -15
4x + 0 = -15
4x = -15

-15/4
I got 3.75, so I rounded that up to 4.
(4, 0)

The points are (0, -5) and (4, 0)

The Equations: y = 2x,   x + y = 3

y = 2x
y = 2(2)
y = 4

(2, 4)


x + y = 3

First I picked 2 for x.

2 + y = 3

If we subtract 2 from both sides of the equation we will get y by itself.

2 - 2 + y = 3 - 2

2 - 2 = 0 so the left hand side becomes

0 + y = 3 - 2

Now y + 0 is the same as y so the left hand side becomes

y = 3 - 2

Now 3 - 2 = 1 so the right side becomes

y = 1

(2, 1)

I don't think any of the work is wrong but the problem is only one point was found for each equation. I need 2 points from each equation.


I'm just here to get some help with an online math course I'm taking.

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#2 2012-07-27 05:12:47

SlowlyFading
Member
Registered: 2012-06-12
Posts: 149

Re: Help me Find Two Points from this Problem and Show your Work!

y = 2x,   x + y = 3

Actually, I'm not exactly sure what's wrong with the problem above. Is there even a problem with that one? Do I need more points? sad


I'm just here to get some help with an online math course I'm taking.

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#3 2012-07-27 05:55:50

bob bundy
Moderator
Registered: 2010-06-20
Posts: 6,269

Re: Help me Find Two Points from this Problem and Show your Work!

hi SlowlyFading

Your working to get (2,4) and (2,1) is all correct.  smile  If you want more points, just choose another value for x, and work out the y values as you have done.

(0,-5) is correct for the first question.

(4,0) is not correct.

Every thing was correct up to

4x = -15

Then it went wrong.  sad

The x coordinate should have been negative.

And I would not have rounded it at all.  When you come to draw the graph, the line will not be in the right place.

Bob

View Image: Slowly7.gif

You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#4 2012-07-27 20:33:58

debjit625
Member
Registered: 2012-07-23
Posts: 89

Re: Help me Find Two Points from this Problem and Show your Work!

SlowlyFading  wrote:

15/4
I got 3.75, so I rounded that up to 4.
(4, 0)

These coordinates or points are from cartesian coordinate system,they all have different meanings,you just cant change it a bit ,if you do the whole system will go wrong...
In short never round up any point of any coordinate,if the answer is in fraction keep it in fraction
So in this case your coordinate will be

SlowlyFading  wrote:

I don't think any of the work is wrong but the problem is only one point was found for each equation. I need 2 points from each equation.

Like you picked 2 for x ,just pick any other number for x you will get another point.

Good Luck

Last edited by debjit625 (2012-07-27 20:35:53)


Debjit Roy
___________________________________________________
The essence of mathematics lies in its freedom - Georg Cantor

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#5 2012-07-30 03:20:52

SlowlyFading
Member
Registered: 2012-06-12
Posts: 149

Re: Help me Find Two Points from this Problem and Show your Work!

Thanks guys!

How does this work:
x + y = 3
x + 2 = 3
-2 -2

-1/1
(3, -1)

It's the only one I'm not sure about..


I'm just here to get some help with an online math course I'm taking.

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#6 2012-07-30 03:42:19

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 83,056

Re: Help me Find Two Points from this Problem and Show your Work!

Hi;

What is (3, -1)?


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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#7 2012-07-30 04:11:26

SlowlyFading
Member
Registered: 2012-06-12
Posts: 149

Re: Help me Find Two Points from this Problem and Show your Work!

The (3, -1) is the point.


I'm just here to get some help with an online math course I'm taking.

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#8 2012-07-30 04:15:01

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 83,056

Re: Help me Find Two Points from this Problem and Show your Work!

Hi;

It is certainly not on x + y = 3.


In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

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#9 2012-07-30 04:17:52

debjit625
Member
Registered: 2012-07-23
Posts: 89

Re: Help me Find Two Points from this Problem and Show your Work!

I think you have one equation and solving it will be like this


Let y be 2

Subtract 2 from both the sides


So your point will be

Now let x be 2

Subtract 2 from both the sides


So your point will be

Normally we use intercept to find any two points of a straight line  i.e... take x as 0 and solve for the equation and then take y as 0 and solve the equation.
If you take x as 0 then y will be 3

and if you take y as 0 then x will be 3

Good Luck


Debjit Roy
___________________________________________________
The essence of mathematics lies in its freedom - Georg Cantor

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#10 2012-07-30 04:23:23

debjit625
Member
Registered: 2012-07-23
Posts: 89

Re: Help me Find Two Points from this Problem and Show your Work!

SlowlyFading  wrote:

The (3, -1) is the point.

This point can't be from the equation

,let substitute the values of x and y in the equation


Last edited by debjit625 (2012-07-30 04:25:39)


Debjit Roy
___________________________________________________
The essence of mathematics lies in its freedom - Georg Cantor

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#11 2012-07-30 04:29:30

SlowlyFading
Member
Registered: 2012-06-12
Posts: 149

Re: Help me Find Two Points from this Problem and Show your Work!

Okay! Thanks. <3


I'm just here to get some help with an online math course I'm taking.

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#12 2012-07-31 04:17:09

SlowlyFading
Member
Registered: 2012-06-12
Posts: 149

Re: Help me Find Two Points from this Problem and Show your Work!

And, how exactly do you graph points like that?


I'm just here to get some help with an online math course I'm taking.

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#13 2012-07-31 05:36:02

bob bundy
Moderator
Registered: 2010-06-20
Posts: 6,269

Re: Help me Find Two Points from this Problem and Show your Work!

see below

Bob

View Image: slowly8.gif

You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#14 2012-08-01 06:15:41

SlowlyFading
Member
Registered: 2012-06-12
Posts: 149

Re: Help me Find Two Points from this Problem and Show your Work!

Thanks!


I'm just here to get some help with an online math course I'm taking.

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#15 2012-08-01 18:47:23

bob bundy
Moderator
Registered: 2010-06-20
Posts: 6,269

Re: Help me Find Two Points from this Problem and Show your Work!

You're welcome.

Bob


You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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