Q. The distance between the foci of the conic $7x^{2} - 9y^{2} = 63$ is equal to
A) 8
B) 4
C) 3
D) 7
Explanation
(a)
Given equation of hyperbola is
$\frac{x^{2}}{9} - \frac{y^{2}}{7} = 1\$
Distance between foci$\ = 2ae = 2\sqrt{2a^{2} + b^{2}}$
$= \ 2\sqrt{9 + 7}$
$= 8$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.