Question 199802
f(x) =y = (-4x) / { (x-9)(x+8)]  =  (-4x)/ ( x^2 -x-72)
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Vertical  asymptotes  at  x=9,,,,x=-8,,,,zeros  of  the  denominator
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horizontal asymptotes  at  y=0,,,,,leading  exponent  of  num  > dem
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x intercept  at  x=0,,,,,zeros  of  numerator
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Domain  is  all  Real  Numbers  except  at  x=-8,,,and  at  x=9.
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To  make  a  rough  sketch,,,use  x-y  coordinate  system,,
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starting  at  - infinity,  y  is  just  positive  and  curve  upward  as  we  move  to  right  and  
goes  to  + infinity  at  x=-8.
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On  the  other  side  of  x=-8 (-7.9)  y is  at  - infinity ,,,curves  upward  to  (0,0) and  then  to  
+ infinity,  at  x=9.  Watch  change  of  direction,  double  curve,  close  to  (0,0)
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On  the other  side  of  x=9 ( x=9.1) y  is  at  - infinity,  and  as  we  move  to  right  it  curves  upward  to  approach y=0 on  the  negative  side.