Solve for x,
\[\frac{ 5 }{ x^2-1 }-\frac{ 2 }{ x }=\frac{ 2 }{ x+1 }\]
I would solve this by multiplying every term on both sides of the equation by the LCD.
The LCD is \(x(x+1)(x-1)\). \[x(x+1)(x-1)\left(\frac{ 5 }{ x^2-1 }\right)-x(x+1)(x-1)\left(\frac{ 2 }{ x }\right)=x(x+1)(x-1)\left(\frac{ 2 }{ x+1 }\right)\] Simplifying: \[5x -2(x+1)(x-1) = 2x(x-1)\]
I think its easier to do this: \[\frac{5}{x^2-1}-\frac{2}{x}=\frac{2}{x+1}\]\[\frac{5}{x^2-1}-\frac{2(x-1)}{x^2-1}=\frac{2}{x}\]\[5x-2x^2-2x=2(x^2-1)\]\[-4x^2+3x+2=0\]
FOIL (x+1)(x-1) \[5x - 2(x^2-1) = 2x^2 - 2x\] Distribute to clear parenthesis \[5x - 2x^2 + 2 = 2x^2- 2x\] Gather all terms to one side (keep the \(x^2\) term positive) \[0 = 4x^2-7x - 2\] Solve the quadratic equation using factoring: \[0 = (x-2)(4x+1)\] \[x = 2\; \text{ and }\; x = \frac{1}{4}\] Both solutions are ok since they won't make any of the original fractions undefined.
I messed up some +- there but the idea is the same.
Thanks to all of you!!
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