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[tex]( \frac{2x-8}{ x^{2 -8x+15 } } - \frac{1}{x-3}) : \frac{1}{ x^{2 - 25 } } [/tex]

Răspuns :

Il luam pe x²-8x+15 si il descompunem:
x²-8x+15=x²-3x-5x+15=x(x-3)-5(x-3)=(x-3)(x-5)
[tex] (\frac{2x-8}{(x-3)(x-5)}- \frac{1}{x-3})* \frac{(x-5)(x+5)}{1}= \\ \frac{2x-8-x+5}{(x-3)(x-5)}*(x-5)(x+5)= \\ \frac{x-3}{x-3}*(x+5)=x+5 [/tex]