maths

Aoami

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x/5 + 7 = 1/3x + 5

How do you solve that? I don't get what to do with the 1/3x (a third of x?) and google is useless

would i be right in thinking that you've gotta multiply both sides by 15 as it's the lowest common multiple of 3 and 5?
 

Wonk

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x/5 + 7 = 1/3x + 5

x/5 = Ω + 31

Ω/5 = 31Ωx

Ω = Laddeys sister.

That's how the wise men always does it :(
 

Ezteq

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umm

x/5 + 7 = 1/3x + 5

something that is one fifth of something plus seven equals the same as one third of something plus five?

lol seriously I don't know, tried to help but I do not believe that I can do mathematical jiggery pokery.
 

tris-

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x/5 + 7 = 1/3x + 5

I got x/x = (1/3)-10

doesnt seem right to me. I thbink you need to do something with recipricals and shit, and I havent for about 2 years.

Edit: a bit more and ive got recipof x = (5/15)-10. Basically the same as the other one ffs.
 

Aoami

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we've never learnt about recipricals, it's a pretty basic module. The only solution I could come up with was x = -15 but that didn't work.
 

tris-

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my answer givews -7 anyway which isnt right.
 

Vae

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Been a very long time since I've done these but here goes:

x/5 +7 = 1/3x +5 then -5 to each side

x/5 +2 = 1/3x then multiply both sides by 3x

3x(squared)/5 +6x =1 then -1 to each side

3x(squared)/5 +6x -1 =0 then multiply by 5

3x(squared) +30x -5 =0

Use quadratic equation formula
x=(-b +-Sqrt(b(squared) -4ac)/2a

x=(-30 +-Sqrt(900+60))/6

So x = 0.16398 or -10.164

Not a very neat answer I admit which makes me wonder if i've made a mistake somewhere (or if the initial formula is correct). However just put these answers back into the original formula and it checks out.
 

Jarahl

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It's something (x) divided with 5 + 7, and then a 3rd of that same something plus 5.

15 from the way I look at it works yes??

15/5 + 7 = (1/3)*15 + 5

15 divided with 5 is 3, 3 + 7 is 10.

One third of 15 is 5, and 5 + 5 is 10.

Am I completely off track? Haven't done any type of math for 10 years I think :p
 

Aoami

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jesus christ this is meant to be a maths for noobs module and it's now giving quadratic equations that look like -2x^2 + 4x = 2.

Thanks for the help guys, Vae's makes most sense so far

edit - with regards that quadratic, would a = -2, b = 4, then c = 0 if i was to put it in the quadratic forumla?
 

Vae

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jesus christ this is meant to be a maths for noobs module and it's now giving quadratic equations that look like -2x^2 + 4x = 2.

Thanks for the help guys, Vae's makes most sense so far

edit - with regards that quadratic, would a = -2, b = 4, then c = 0 if i was to put it in the quadratic forumla?

Aoami regarding your example quadratic above -2x^2 + 4x = 2

You have to rearrange this to get it so it equals 0

So -2x^2 + 4x -2 = 0

Then a=-2, b=4 and c=-2
 

Vae

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It's something (x) divided with 5 + 7, and then a 3rd of that same something plus 5.

15 from the way I look at it works yes??

15/5 + 7 = (1/3)*15 + 5

15 divided with 5 is 3, 3 + 7 is 10.

One third of 15 is 5, and 5 + 5 is 10.

Am I completely off track? Haven't done any type of math for 10 years I think :p

Jarahl you'd be right if the formula was 1/3 of x (i.e. x/3) but from the initial formula it's 1 divided by 3x (1/3x) which makes it far more complicated unless Aoami has written it down wrong in the first post.
 

Aoami

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he's right, it's a third of x, not 1/3x, wasn't sure of the best way to write it sorry :p

Thanks for the help re. quadratics
 

Vae

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he's right, it's a third of x, not 1/3x, wasn't sure of the best way to write it sorry :p

Thanks for the help re. quadratics

Well that makes it a whole lot easier which would make sense if this is maths for Noobs. You wouldn't expect x to be anything except a nice round integer on one of those courses which is what I was alluding to when I got the other answers.

Ingafgrinn's answer is far neater than mine but he cheated with a pdf :p
 

noblok

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In that case...

x/5 + 7 = x/3 + 5

7-5 = x/3 - x/5

2 = (5x-3x)/15

30 = 2x

15 = x
 

Jarahl

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Jarahl you'd be right if the formula was 1/3 of x (i.e. x/3) but from the initial formula it's 1 divided by 3x (1/3x) which makes it far more complicated unless Aoami has written it down wrong in the first post.

That's the way I understood it, and apparently it was right too :D Guess all you math geniuses thinks everything is far more complicated than it really is ;)
 

CorNokZ

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Step the fuck back and let me get in here

ti89.jpg

solve(x/5+7=1/3x+5,x)

x = 15

TI-89 FUCK YEAH!!!
 

Lucius

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The best way to start these questions is to get all the x's on one side .. then it will be easier :).
 

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