Question 918037
Graph the ellipse 
x^2+4y^2=64
4y^2=(64-x^2) 
y^2=(64-x^2)/4
y=±(64-x^2)^.5/2
see graph below:
{{{ graph( 300, 300, -10, 10, -10, 10,(64-x^2)^.5/2,-(64-x^2)^.5/2) }}}