Answer
$\frac{x^2}{36}+\frac{y^2}{11}=1$
Work Step by Step
Major axis is horizontal.
Foci: $(±c,0)=(±5,0)$
$c=5$
Major axis: $Length=2a$
$2a=12$
$a=6$
$a^2=b^2+c^2$
$b^2=a^2-c^2=6^2-5^2=36-25=11$
$b=\sqrt {11}$
Equation of the ellipse:
$\frac{x^2}{a^2}+\frac{y^2}{b^2}=1$
$\frac{x^2}{6^2}+\frac{y^2}{(\sqrt {11})^2}=1$
$\frac{x^2}{36}+\frac{y^2}{11}=1$
