Math Is Fun Forum

misheeru

Member

Registered: 2010-02-18

Posts: 4,594

Re: Equations with parenthesis?

Oooohh is 4c^4 d^2 better?

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Of Moons, Birds and Monsters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Equations with parenthesis?

Yep, your original answer was darn close!

Mind putting the whole answer together?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

misheeru

Member

Registered: 2010-02-18

Posts: 4,594

Re: Equations with parenthesis?

I mind very much actually.

Anyways before simplifying is 12 - 12c²d - 4c²d + 4c^4 d² good or just darn close?

Last edited by misheeru (2011-01-14 09:04:31)

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Of Moons, Birds and Monsters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Equations with parenthesis?

That is correct. But in the interest of saving paper you should combine like terms.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

misheeru

Member

Registered: 2010-02-18

Posts: 4,594

Re: Equations with parenthesis?

Yes, wouldn't want to upset the environmentalists.

12 - 12c²d - 4c²d + 4c^4 d²

= 12 -16c^2 d + 4c^4 d^2?

Last edited by misheeru (2011-01-14 09:10:12)

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Of Moons, Birds and Monsters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Equations with parenthesis?

That is correct. Need another one I think.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

misheeru

Member

Registered: 2010-02-18

Posts: 4,594

Re: Equations with parenthesis?

Me too, especially since I am not sure what to do with this one:

(a + b - c)(a + b + c)

There are 3 per parenthesis rather then 2... do I need to do this one differently?

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Of Moons, Birds and Monsters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Equations with parenthesis?

Well, you cannot use foil or can you?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

misheeru

Member

Registered: 2010-02-18

Posts: 4,594

Re: Equations with parenthesis?

I don't know, can I? I mean there is an extra term in each parentheses that will be neglected if I use regular foil, will it not?

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Of Moons, Birds and Monsters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Equations with parenthesis?

Yes, that is why foil is such garbage. I do not use it. Does your teacher demand it?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

misheeru

Member

Registered: 2010-02-18

Posts: 4,594

Re: Equations with parenthesis?

Yep.

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Of Moons, Birds and Monsters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Equations with parenthesis?

Did he/she/it explain a method to use foil on a trinomial like that?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

misheeru

Member

Registered: 2010-02-18

Posts: 4,594

Re: Equations with parenthesis?

No... but I found an example.

The example seem rather confusing... but I'm going to try and figure if you...

Would you like to see it? I can type it out here. Maybe you can explain it better.

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Of Moons, Birds and Monsters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Equations with parenthesis?

Type it out please. I mean now!

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

misheeru

Member

Registered: 2010-02-18

Posts: 4,594

Re: Equations with parenthesis?

Well I never...

Ex: ( a + b - 3)(a + b + 5)
   
    = [(a + b) - 3)] [(a + b) + 5)]
    replace a + b with x; x = a + b

    = (x - 3)(x + 5) = x² + 2x + 5
    replace x with a + b

     = (a + b)² + 2 (a + b) - 15
     
= a² + 2ab + b² + 2a + ab - 15

Last edited by misheeru (2011-01-14 10:00:41)

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Of Moons, Birds and Monsters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Equations with parenthesis?

Please check your first line again.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

misheeru

Member

Registered: 2010-02-18

Posts: 4,594

Re: Equations with parenthesis?

sorry, forgot the 5

i edited the original post

Last edited by misheeru (2011-01-14 10:02:28)

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Of Moons, Birds and Monsters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Equations with parenthesis?

That answer is darn close. Check your work you have made an error.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

misheeru

Member

Registered: 2010-02-18

Posts: 4,594

Re: Equations with parenthesis?

That is not my work! That is the example given to me!

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Of Moons, Birds and Monsters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Equations with parenthesis?

Have you copied it correctly? That part is yours...

You have:

You need this:

See it now?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Sarah Rebekah 14

Guest

Re: Equations with parenthesis?

Hi Guys.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Equations with parenthesis?

Hello! Eaten yet?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

misheeru

Member

Registered: 2010-02-18

Posts: 4,594

Re: Equations with parenthesis?

Heya Sarah!

Yep bobbym. I just checked, I copied their answer down exactly.

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Of Moons, Birds and Monsters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Equations with parenthesis?

Do not worry about it. It is a typo in the book my answer is correct.

I did not know that you could follow the substitution that was made. Did you?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

misheeru

Member

Registered: 2010-02-18

Posts: 4,594

Re: Equations with parenthesis?

Well I am confused... and I still do not know how to solve the problem I posted earlier...

No, I have no idea what you are even talking about.

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Of Moons, Birds and Monsters