Equations

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Do you want to show your working ? :smile:

Shift the fraction to the other side, multiply by t to get rid of the fraction, factorise, divide to get k on one side and then simply rearrange.

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Reply 21

spotify95

Original post by junyte

Did you mean like this ? :smile:

Thanks

Yep thats pretty much right :smile:

Reply 22

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Original post by Apologetic Cube

5k = 3t - \frac{3k}{t}

5kt = 3t - 3k

5kt + 3k = 3t

k(5t+3) = 3t

k = \frac{3t}{5t+3}

Original post by EastGuava

For the second one I got k = 3t/5t+3 :eyeball:

I got 3t^2 as the numerator :s-smilie:

I think you forgot to multiply 3t by t in line 2.

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Reply 23

EastGuava

Same working out as Apologetic Cube.

Original post by majmuh24

I got 3t^2 as the numerator :s-smilie:

I think you forgot to multiply 3t by t in line 2.

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I didn't realise you have to do that...?

Reply 24

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Original post by EastGuava

Same working out as Apologetic Cube.

I didn't realise you have to do that...?

If you multiply the fraction by t, you have to multiply the rest of the things on that line as well :tongue:

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Thats what i`ve got

Original post by junyte

Thats what i`ve got

The answer on the second to last line is right, why did you change it on the last line?

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Reply 27

EastGuava

Original post by majmuh24

If you multiply the fraction by t, you have to multiply the rest of the things on that line as well :tongue:

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Yeah, makes sense I guess.

OP, you're welcome for us completing your work :P you should have listened in GCSE maths though!

Reply 28

junyte

Original post by majmuh24

The answer on the second to last line is right, why did you change it on the last line?

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Oh my mistake, yeah you are right :wink:

the answer is

is it possible to simplify it or is it in its simplest form ?

Reply 29

junyte

Original post by EastGuava

Yeah, makes sense I guess.

OP, you're welcome for us completing your work :P you should have listened in GCSE maths though!

Yeah i know... i really appreciate it guys. Im not expecting just an answer im trying to understand it myself :smile:

Reply 30

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Original post by junyte

Oh my mistake, yeah you are right :wink:

the answer is

is it possible to simplify it or is it in its simplest form ?

I would leave it as that :smile:

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Reply 31

Zenomorph

why not:

If 5K = 3t - (3K) / t

then 5K + 3K / t = 3t

(5Kt + 3K) / t = 3t

8K = 3t

K = 3t/8

Reply 32

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Original post by Zenomorph

why not:

If 5K = 3t - (3K) / t

then 5K + 3K / t = 3t

(5Kt + 3K) / t = 3t

8K = 3t

K = 3t/8

How did you get from line 3 to line 4?

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Reply 33

TheIrrational

Original post by Zenomorph

why not:

If 5K = 3t - (3K) / t

then 5K + 3K / t = 3t

(5Kt + 3K) / t = 3t

8K = 3t

K = 3t/8

You did 5kt + 3k = 8kt

Which is incorrect

Reply 34

Phichi

All the comments about this being 'undergrad' and no one can agree on the answer!

Reply 35

ThatPerson

Original post by junyte

Hi guys,

I need to solve these two equations by making k the subject of each of the following equations. Also i need to show each step of my working.... I have no idea how to do it. Please Help !!!!!!

Despite you doing this as an undergraduate, if you want the fastest/best help, label the thread according to the content itself (ie if you're doing A Level content in a undergrad course, label it "sixth form").

Reply 36

spotify95

Original post by Zenomorph

why not:

If 5K = 3t - (3K) / t

then 5K + 3K / t = 3t

(5Kt + 3K) / t = 3t

8K = 3t

K = 3t/8

No, you've left the denominator of t in!

I agree up to 5k + 3k/t = 3t

Can't you either:

1) Multiple the right hand side by t to get rid of the denominator, that gives 8k = 3t^2
2) Multiple the whole thing by t, to give 5kt + 3k = 3t^2, then go from there.

Strange how a simple equation is stumping even 1st year university students! :biggrin: