Answer:
A) x²/25 + y²/9 = 1
Step-by-step explanation:
The major axis length is the sum of distances to the foci from the ellipse, 10. So the semi-major axis has length 10/2 = 5. The foci are on the x-axis, so the ellipse is oriented horizontally.
The semi-minor axis is the other leg of the right triangle having the focus and center as one leg, and the semi-major axis as the hypotenuse. This is obviously a 3-4-5 triangle, so the semi-minor axis length is 3.
When the ellipse is horizontal, the formula for it is ...
... (x/(semi-major axis))² + (y/(semi-minor axis))² = 1
... (x/5)² + (y/3)² = 1
... x²/25 + y²/9 = 1
