Question 1207267
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1st Hint: 
One setup equation would be {{{1/x + 1/(x+9) = 5/12}}}


2nd hint:
Multiply both sides by the LCD 12x(x+9) to arrive at {{{12(x+9) + (12x) = 5x(x+9)}}}


3rd hint:
Expand everything out and get terms to one side. 
You should get {{{5x^2+21x-108=0}}}
In which you can use the quadratic formula.
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