Difference between revisions of "2020 AMC 12B Problems/Problem 8"

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==Problem==
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#REDIRECT [[2020 AMC 10B Problems/Problem 9]]
 
 
How many ordered pairs of integers <math>(x,y)</math> satisfy the equation <cmath>x^{2020}+y^2=2y</cmath>
 
 
 
==Solution==
 
Set it up as a quadratic in terms of y:
 
<cmath>y^2-2y+x^{2020}=0</cmath>
 
Then the discriminant is
 
<cmath>\Delta = 4-4x^{2020}</cmath>
 
This will clearly only yield real solutions when <math>x^{2020} \leq 1</math>
 
 
 
==See Also==
 
 
 
{{AMC12 box|year=2020|ab=B|num-b=7|num-a=9}}
 
{{MAA Notice}}
 

Latest revision as of 21:28, 12 February 2020