Answer
$\frac{x^2}{4}+\frac{y^2}{3}=1$
Work Step by Step
Major axis is horizontal.
Foci: $(±c,0)=(±1,0)$
$c=1$
Vertices: $(±a,0)=(±2,0)$
$a=2$
$a^2=b^2+c^2$
$b^2=a^2-c^2=2^2-1^2=4-1=3$
$b=\sqrt 3$
Equation of the ellipse:
$\frac{x^2}{a^2}+\frac{y^2}{b^2}=1$
$\frac{x^2}{2^2}+\frac{y^2}{(\sqrt 3)^2}=1$
$\frac{x^2}{4}+\frac{y^2}{3}=1$