Difference between revisions of "2000 AMC 10 Problems/Problem 15"

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==Problem==
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#REDIRECT [[2000 AMC 12 Problems/Problem 11]]
 
 
Two non-zero real numbers, <math>a</math> and <math>b</math>, satisfy <math>ab=a-b</math>.  Find a possible value of <math>\frac{a}{b}+\frac{b}{a}-ab</math>.
 
 
 
<math>\mathrm{(A)}\ -2 \qquad\mathrm{(B)}\ -\frac{1}{2} \qquad\mathrm{(C)}\ \frac{1}{3} \qquad\mathrm{(D)}\ \frac{1}{2} \qquad\mathrm{(E)}\ 2</math>
 
 
 
==Solution==
 
 
 
<math>ab=a-b</math>
 
 
 
<math>\frac{a}{b}+\frac{b}{a}-ab=\frac{a^2+b^2}{ab}-ab=\frac{-a^2b^2+a^2+b^2}{ab}</math>
 
 
 
<math>\frac{-a^2+2ab-b^2+a^2+b^2}{ab}=2</math>.
 
 
 
E.
 
 
 
==See Also==
 
 
 
{{AMC10 box|year=2000|num-b=14|num-a=16}}
 

Latest revision as of 22:54, 26 November 2011