the vertex of y^2 - 8y + 24 = x is...

(9,3) (24,0) (8,4) (4,8) or none of these

Complete the square.

y^2 - 8y + 24 = y^2 - 8y + 16 + 8
= (y-4)^2 +8 = x
The lowest possible value of x is at y=4, where x=8.

That is one of your choices.. The parabola (which is "on its side") opens up to the right of that point.