Marks brother is five older than mark their combined ages add up to 23 how ild is mark

Since Mark's brother is five years older than Mark and their combined ages add up to 23 than Mark must be 9.

Since 9 + 14 = 23, and 14 - 9 = 23 
Mark brother is 14 but Mark is 9

Mark is 9 years old.
Hope this helps :0

X^2 - 4x +(4/2^2) + y^2 + 8y + (8/2^2) = -4 + (4/2^2) + (8/2^2)(x + 2)^2 + (y + 4)^2 = -4 + 4 + 16your center is (-2, -4) and the radius is the sqrt of -4 + 4 + 16 which is 4