Question 794458
find an equation of the ellipse with the center at the origin one focus at (3,0) and one vertex at (-4,0) 
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Ellipse has a horizontal major axis with given center at (0,0)
Its standard form of equation: {{{x^2/a^2+y^2/b^2=1}}}, a>b, (h,k) =(x,y)coordinates of center
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a=4 (distance from center to vertex on the horizontal major axis)
a^2=16
c=3 (distance from focus to vertex on the horizontal major axis)c^2=9
c^2=9
c^2=a^2-b^2
b^2=a^2-c^2=16-9=7
equation: {{{x^2/16+y^2/7=1}}}