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# One Equation, Two Variables

Pro Problems > Math > Algebra > Equations > Systems of Equations > Non-Linear

## One Equation, Two Variables

Usually we say that if we have two variables, we need two equations to solve, and if we have three variables, we need three equations to solve. This is not 100% true, however, and the problem below is a good example of a single equation in two variables which produce a single ordered pair solution.

Solve for the ordered pair (x,y) such that x2 + y2 - 2x + 4y = -5

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Problem by Mr. Twitchell

## Solution

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