Question 875555
Ellipse: {{{(x-h)^2/a^2 + (y-k)^2/b^2 = 1 }}} 
where Pt(h,k) is the center. (a variable positioned to correspond with major axis)
 a and b  are the respective vertices distances from center
 and ±{{{sqrt(a^2-b^2)}}}are the foci distances from center: a > b
center at (2,3), one vertex at (6, 3),  a = (6-2) = 4
{{{(x-2)^2/4^2 + (y-3)^2/b^2 = 1 }}} 
C(2,3)and one focus at (-1, 3). c = 3,  3^2 = (a^2 - b^2), 9 = 16 - b^2
{{{(x-2)^2/16 + (y-3)^2/7 = 1 }}}