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February 26th, 2017, 04:52 AM   #1
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Making a letter the subject of an equation

Hey guys,

I've been studying maths for a few months but I'm really struggling with making a letter the subject when it is on both sides of the equations (in a fraction) i.e. please see below (how would i make t the subject)? The part I struggle with is removing t from one side (there is only '1' 't' on either side so how do i get rid of one without removing the other?)

5y - 11/t = 13 - 7y/t


Any help is much appreciated
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February 26th, 2017, 05:00 AM   #2
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$5y-\dfrac{11}{t}=13-\dfrac{7y}{t}$

start by multiplying every term by $t$ ...

$5yt-11=13t-7y$

move all terms with a factor of $t$ to the same side, all terms w/o to the other side ...

$5yt -13t=11-7y$

factor out $t$ ...

$t(5y-13)=11-7y$

divide both sides by $5y-13$ ...

$t=\dfrac{11-7y}{5y-13}$
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February 26th, 2017, 05:04 AM   #3
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Thank you so much!!!
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March 3rd, 2017, 04:59 AM   #4
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Equivalently, starting with
add to both sides:


Subtract 13 from both sides:


Invert both sides:


Finally, multiply both sides by 11- 7y:
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