Q. The locus of centre of circle which touches the circle $x^2+y^2-8 x-8 y+23=0$ and the $y$-axis is a conic whose latus rectum is
Conic Sections
Solution:
$r=\sqrt{4^2+4^2-23}=3$
Locus of centre is a parabola with focus $(4,4)$ and directrix $x=-3$