An ellipse is represented by the equation the fraction with numerator open paren x minus 5 close paren squared and denominator 625 plus the fraction with numerator open paren y minus 4 close paren squared and denominator 225 is equal to 1 Each directrix of this ellipse is a ________________________ from the center on the major axis.

The larger denominator is 625 under the x-term, so the major axis is horizontal and a = 25. The other denominator gives b = 15, so c = √(a² − b²) = √(625 − 225) = 20. Each directrix is a vertical line, and its distance from the center is a²/c = 625/20 = 31.25 units, matching “vertical line that is 31.25 units.”

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