Difference between revisions of "1986 AIME Problems/Problem 1"

(Problem)
(Solution)
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== Solution ==
 
== Solution ==
 +
Let <math>y = \sqrt[4]{x}</math>. Then we have
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'''<math>y(7 - y) = 12</math>''', or, by simplifying,
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'''<math>y^2 - 7y + 12 = (y - 3)(y - 4) = 0</math>'''.
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This means that <math>\sqrt[4]{x} = y = 3</math> or '''<math>4</math>'''.
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Thus the sum of the possible solutions for '''<math>x</math>''' is '''<math>4^4 + 3^4 = 337</math>''', the answer.
  
 
== See also ==
 
== See also ==
 
* [[1986 AIME Problems]]
 
* [[1986 AIME Problems]]

Revision as of 09:41, 28 October 2006

Problem

What is the sum of the solutions to the equation $\sqrt[4]{x} = \frac{12}{7 - \sqrt[4]{x}}$?

Solution

Let $y = \sqrt[4]{x}$. Then we have $y(7 - y) = 12$, or, by simplifying, $y^2 - 7y + 12 = (y - 3)(y - 4) = 0$. This means that $\sqrt[4]{x} = y = 3$ or $4$. Thus the sum of the possible solutions for $x$ is $4^4 + 3^4 = 337$, the answer.

See also