SOLUTION: how can you tell if the equation is a circle, an ellipse, parabola or hyperbola with out graphing or putting it in standard form? for example: x^2 + 4x + y^2 +4y - 8 = 0 is a c

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: how can you tell if the equation is a circle, an ellipse, parabola or hyperbola with out graphing or putting it in standard form? for example: x^2 + 4x + y^2 +4y - 8 = 0 is a c      Log On


   



Question 133047: how can you tell if the equation is a circle, an ellipse, parabola or hyperbola with out graphing or putting it in standard form?
for example:
x^2 + 4x + y^2 +4y - 8 = 0 is a circle,
but how do you tell w/o putting it in standard form?
please help differ all shapes.

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
If the x^2 and the y^2 have the same coefficient you have a circle.
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If they have the same sign but different coefficients you have an ellipse
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If they have different signs you have a hyperbola.
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Cheers,
Stan H.