Final answer:
The foci of the ellipse defined by x²/9 + y²/4 = 1 are at (√5, 0) and (-√5, 0) because the distance c is the square root of 5, derived from the formula c² = a² - b² where a is the length of the semi-major axis and b is the length of the semi-minor axis.
Step-by-step explanation:
The foci of the ellipse represented by the equation x²/9 + y²/4 = 1 can be found using the relationship c² = a² - b², where c is the distance from the center to each focus, a is the semi-major axis, and b is the semi-minor axis of the ellipse.
In this equation, a² is larger than b², so the semi-major axis is the square root of 9 (which is 3), and the semi-minor axis is the square root of 4 (which is 2). Thus, c² is 3² - 2², which equals 9 - 4, therefore c² is 5. The distance c is then the square root of 5, giving us the foci located at (√5, 0) and (-√5, 0).
So, the correct answer is B) (√5, 0).