2020 AMC 12B Problems/Problem 8

Revision as of 20:21, 7 February 2020 by N828335 (talk | contribs) (Solution)

Problem

How many ordered pairs of integers $(x,y)$ satisfy the equation \[x^{2020}+y^2=2y\]

Solution

Set it up as a quadratic in terms of y: \[y^2-2y+x^{2020}=0\] Then the discriminant is \[\Delta = 4-4x^{2020}\] This will clearly only yield real solutions when $x^{2020} \leq 1$

See Also

2020 AMC 12B (ProblemsAnswer KeyResources)
Preceded by
Problem 7
Followed by
Problem 9
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All AMC 12 Problems and Solutions

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