<PRE><B>Question 276896</B>
how does x+5/x-5 -  x-5/x+5= 20x/(x-5)(x+5) 
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(x+5)/(x-5) - (x-5)/(x+5)
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lcd = (x-5)(x+5)
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Write each fraction with the lcd as its denominator:
[(x+5)^2]/lcd - [(x-5)^2/lcd]
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Combine the numerators over the lcd:
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[x^2+10x + 25 - (x^2 - 10x + 25)]/lcd
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[x^2 + 10x + 25 - x^2 + 10x - 25]/lcd
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= 20x/lcd
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= 20x/[(x^2-25)
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Cheers,
Stan H.</PRE>