MathematicsEasy74×since 2004Q3740The eccentricity of an ellipse, with its centre at the origin, is 12{1 \over 2}21. If one of the directrices is x=4x=4x=4, then the equation of the ellipse is :A4x2+3y2=14{x^2} + 3{y^2} = 14x2+3y2=1B3x2+4y2=123{x^2} + 4{y^2} = 123x2+4y2=12C4x2+3y2=124{x^2} + 3{y^2} = 124x2+3y2=12D3x2+4y2=13{x^2} + 4{y^2} = 13x2+4y2=1Check answerSkip