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Answer:
x^2/1 +y^2/81 = 1
Explanation:
We know that the equation of a unit circle is ...
x^2 +y^2 = 1 . . . . . equation of a unit circle
We also know that replacing x with x/a in a function will expand the graph by a factor of 'a'. Similarly, replacing y with y/b will do the same in the vertical direction.
An ellipse is a circle that has had different expansion factors applied along its different axes. Here, the given points tell us the center of the ellipse is (0, 0), and that it has been expanded by a factor of 9 in the y-direction and a factor of 1 in the x-direction This means the equation for it would be ...
(x/1)^2 +(y/9)^2 = 1 . . . . . equation for desired ellipse
In the required form, this is ...