The equation of the ellipse whose foci are ( ±5 , 0 ) and one of its dierctrix is 5x = 36 , is
Foci ( ± 5 , 0 ) ≡ ( ± ae , 0) . Directrix (x=365)≡x=ae
So , ae=365,ae=5⇒a=6 and e=56
Therefore , b = 6 √1−2536=6√116=√11
Hence, the equation is x236+y211=1