Answer
$\frac{x^2}{25}+\frac{y^2}{21}=1$
Work Step by Step
Major axis is horizontal.
$(±5,0)=(±a,0)$
$a=5$
$(±2,0)=(±c,0)$
$c=2$
$a^2=b^2+c^2$
$b^2=5^2-2^2=25-4=21$
$b=\sqrt {21}$
Standard form when major axis is horizontal:
$\frac{x^2}{a^2}+\frac{y^2}{b^2}=1$
$\frac{x^2}{5^2}+\frac{y^2}{(\sqrt {21})^2}=1$
$\frac{x^2}{25}+\frac{y^2}{21}=1$
