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Oct 22nd, 2009

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math question

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how do i solve this problem
r+5(r-2)=28
3(r+4)+5(r+2)=102

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James19142

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Oct 22nd, 2009

Re: math question

This question seemingly has nothing to do with c++. In the future dont post math related questions in the programming forums.
As for your problem, what does the question ask you to do? Do you have to solve for the variable r?

Grn Xtrm

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Oct 22nd, 2009

Re: math question

1st) Read post 1, although if you PM, someone that knows a little math, he might help you.

2)

C++ Syntax (Toggle Plain Text)
Let A = r+5(r-2)=28
Let B = 3(r+4)+5(r+2)=102 
 
 
//Break down A
A = r+5(r-2) = 28
= r + 5r - 10 = 28 //distributive rule
= 6r - 10 = 20 //add like trms
= 6r = 20 + 10  //remember switching numbers to the opposite sides mean change its operatorion from + to minus, * to / and vice-versa
so, 6r = 20 + 10,
6r = 30
r = 30/6 = 15/3 = 5
Let A = r+5(r-2)=28
Let B = 3(r+4)+5(r+2)=102 


//Break down A
A = r+5(r-2) = 28
= r + 5r - 10 = 28 //distributive rule
= 6r - 10 = 20 //add like trms
= 6r = 20 + 10  //remember switching numbers to the opposite sides mean change its operatorion from + to minus, * to / and vice-versa
so, 6r = 20 + 10,
6r = 30
r = 30/6 = 15/3 = 5

C++ Syntax (Toggle Plain Text)
//Break down of B
Let B = 3(r+4)+5(r+2)=102 
 
B = 3r + 12 + 10r + 20 = 102 //Distributive property
=  3r + 10r + 12 + 20 = 102 // re-arrange like terms
= 13r + 32 = 102 //add like terms
 = 13r = 102 - 32 //bring together like terms
 = 13r = 70
 = r = 70/13
//Break down of B
Let B = 3(r+4)+5(r+2)=102 

B = 3r + 12 + 10r + 20 = 102 //Distributive property
=  3r + 10r + 12 + 20 = 102 // re-arrange like terms
= 13r + 32 = 102 //add like terms
 = 13r = 102 - 32 //bring together like terms
 = 13r = 70
 = r = 70/13

firstPerson

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Oct 22nd, 2009

Re: math question

Click to Expand / Collapse Quote originally posted by firstPerson ...

(Toggle Plain Text)
A = r+5(r-2) = 28
= r + 5r - 10 = 28 //distributive rule
= 6r - 10 = 20 //add like trms
A = r+5(r-2) = 28 = r + 5r - 10 = 28 //distributive rule = 6r - 10 = 20 //add like trms

Where'd the 28 go and the 20 come from?

Last edited by Dave Sinkula; Oct 22nd, 2009 at 10:20 am.

Dave Sinkula

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long time no c

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Oct 22nd, 2009

Re: math question

Also with B: this B = 3r + 12 + 10r + 20 = 102 //Distributive property is completely wrong. I have no idea what you're trying to do here.
Look, if r(B)=70/13=5.38... (according to you) then if you substitute 'r' with 5.38... in the original formula, you should get 102; which you don't.

the answer to B is 10. But I'm not going to show the math here, because the OP needs to learn to do his/her own damn homework.

Last edited by Nick Evan; Oct 22nd, 2009 at 10:50 am.

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Oct 23rd, 2009

Re: math question

Lol, I was high when I posted that, sorry.

firstPerson

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Re: math question

Click to Expand / Collapse Quote originally posted by firstPerson ...

Lol, I was high when I posted that, sorry.

You shouldn't drink and drive and you should smoke and do math. That's how people come up with stuff like the Large Hadron Collider: very dangerous

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Oct 23rd, 2009

Re: math question

Click to Expand / Collapse Quote originally posted by firstPerson ...

1st) Read post 1, although if you PM, someone that knows a little math, he might help you.

2)
C++ Syntax (Toggle Plain Text)
Let A = r+5(r-2)=28
Let B = 3(r+4)+5(r+2)=102 
 
 
//Break down A
A = r+5(r-2) = 28
= r + 5r - 10 = 28 //distributive rule
= 6r - 10 = 20 //add like trms
= 6r = 20 + 10  //remember switching numbers to the opposite sides mean change its operatorion from + to minus, * to / and vice-versa
so, 6r = 20 + 10,
6r = 30
r = 30/6 = 15/3 = 5
Let A = r+5(r-2)=28 Let B = 3(r+4)+5(r+2)=102 //Break down A A = r+5(r-2) = 28 = r + 5r - 10 = 28 //distributive rule = 6r - 10 = 20 //add like trms = 6r = 20 + 10 //remember switching numbers to the opposite sides mean change its operatorion from + to minus, * to / and vice-versa so, 6r = 20 + 10, 6r = 30 r = 30/6 = 15/3 = 5
C++ Syntax (Toggle Plain Text)
//Break down of B
Let B = 3(r+4)+5(r+2)=102 
 
B = 3r + 12 + 10r + 20 = 102 //Distributive property
=  3r + 10r + 12 + 20 = 102 // re-arrange like terms
= 13r + 32 = 102 //add like terms
 = 13r = 102 - 32 //bring together like terms
 = 13r = 70
 = r = 70/13
//Break down of B Let B = 3(r+4)+5(r+2)=102 B = 3r + 12 + 10r + 20 = 102 //Distributive property = 3r + 10r + 12 + 20 = 102 // re-arrange like terms = 13r + 32 = 102 //add like terms = 13r = 102 - 32 //bring together like terms = 13r = 70 = r = 70/13

I thought you purposely gave him a dud answer so he would hand it in. Well done you had me fooled.

iamthwee

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Oct 23rd, 2009

Re: math question

niek_e is correct about the second equation having r = 10. I didn't see anyone give a correct answer for the first, so I will: r = 19/3.

Click to Expand / Collapse Quote originally posted by niek_e ...

You shouldn't drink and drive and you should smoke and do math. That's how people come up with stuff like the Large Hadron Collider: very dangerous

Ha. I refuse to subscribe to the theory that the LHC could end the world.

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Oct 23rd, 2009

Re: math question

Click to Expand / Collapse Quote originally posted by iamthwee ...

I thought you purposely gave him a dud answer so he would hand it in. Well done you had me fooled.

Maybe, I don't remember what I was thinking at that time.

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