Question 295500
{{{((x^2)/81)-((y^2)/(-144/7))=1}}}
{{{(1/81)*x^2+(7/144)*y^2=1}}}
{{{(7/144)*y^2=1-(1/81)*x^2}}}
{{{y^2=(144/7)*(1-(1/81)*x^2)}}}
{{{y=0 +- sqrt((144/7)*(1-(1/81)*x^2))}}}
It's an ellipse. 
{{{ graph( 300, 300, -10, 10, -10, 10, 
sqrt((144/7)*(1-(1/81)*x^2)),
-sqrt((144/7)*(1-(1/81)*x^2))
) }}}