Saturday, May 11, 2013

solve 4(x+2)^-1 - (3x)^-1 = 10(x+2)^-1

We'll rewrite it to make it easier to work with. In particular we move all like terms to the same side of the equation: 


 
which simplifies to... 

%0D%0A%28-+1%29%2F%283x%29+=+6%2F%28x%2B2%29%0D%0A 

Now notice that this is a proportion, so we can cross multiply then divide: 
%0D%0A%28-1%29%28x%2B2%29=%286%29%283x%29%0D%0A 
%0D%0A-x-2=18x%0D%0A 

-x%2Bx-2=18x%2Bx 
then x = -2/19 


:)

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