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2014-06-29T13:37:17-03:00
 \frac{x+1}{x-8} + \frac{x+1}{x} =1 \\  \frac{x(x+1)+(x+1)(x-8)=1(x-8)x}{(x-8)x}  \\  x^{2} +x+ x^{2} -8x+x-8= x^{2} -8x \\ 2 x^{2} -6x-8= x^{2} -8x \\ 2 x^{2} - x^{2} -6x+8x-8=0 \\  x^{2} +2x-8=0

Δ = b² - 4.a.c 
Δ = 2² - 4 . 1 . -8 
Δ = 4 - 4. 1 . -8 
Δ = 36

x = (-b +- √Δ)/2a
x' = (-2 + √36)/2.1          x'' = (-2 - √36)/2.1
x' = 4 / 2                        x'' = -8 / 2
x' = 2                             x'' = -4
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